Electrowetting and electrostatic screen display systems, color displays and transmission means

ABSTRACT

Methods and related devices for manipulating ambient light and various light sources for applications including colour displays, screen displays and colored coverings for a multitude of items is disclosed. Methods and related devices for manipulating light for decorative, signaling and other purposes are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.09/803,445, filed Mar. 9, 2001, which claimed priority to, andincorporated by reference, U.S. Patent Application No. 60/188,474, filedMar. 10, 2000.

FIELD OF THE INVENTION

The invention relates to surfaces with changeable colours. Moreparticularly, the invention relates to colour screen displays andmethods for manipulating the colours of the displays.

BACKGROUND OF THE INVENTION

There are various well-known electronic display means enabling someoneholding a stylus to ‘draw’ or ‘write’ on said display means, and to seewhat they have drawn appear on, for example, a colour LCD screen.

To accomplish the above, it is also known that a suitable electricalcharge at an electrode adjacent to an oil droplet, where said droplet islocated within a suitable electrolyte, and where said droplet isseparated from said electrode by a hydrophobic polymer layer, can inducea change in the shape of an oil droplet, thus changing the colour of apixel on a screen.

It is similarly known that, in a similar system, a polar liquid dropletmay replace an oil droplet. The polar liquid droplet may be moved whenarranged with an insulating liquid surrounding it, with a ground planewithin proximity to the droplet/insulating liquid reservoir, and with ahydrophobic polymer insulating layer located in between the droplet andmore than one separately-addressable adjacent electrodes. This can beaccomplished by charging, one by one, a number of electrodes adjacent tosaid droplet so as to cause the hydrophobic property of the localpolymer surface to become hydrophilic, and causing the droplet to beattracted successively to first one and then another chargedelectrode-proximate location. Arrangements for achieving these effectsare described in existing prior art.

To date, however, there are few if any colour display means which areelectronically ‘writeable’ with a stylus, as well as beingelectronically ‘erasable’, and which are low-cost to manufacture.

Therefore, there is a need for a low-cost electronic display means whichcan display in colour what is drawn or written on its display area, andcan later electronically erase the same displayed items. Further, thereis a need for low-cost colour display means which do not employ, orwhich do not require, a stylus to achieve satisfactory addressing. Thepurpose of some of the following inventions is to exploit suchapproaches for a new application, that of directing light onto, orthrough, differently-coloured light filters so as to provide variousdifferent and innovative display means.

SUMMARY OF THE INVENTION

Methods and related devices for manipulating ambient light and variouslight sources for applications including colour displays, screendisplays and colored coverings for a multitude of items is disclosed.Methods and related devices for manipulating light for decorative,signaling and other purposes are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a preferred display system withstylus which utilizes light which falls onto the screen surface.

FIG. 2 is a cross-sectional view of another preferred display systemwith stylus which utilizes light falling onto the screen surface.

FIG. 3 is cross-sectional view of a preferred display system which showsthe movement of a electrically charged droplet.

FIG. 4 is a cross-sectional view of a preferred backlit display system.

FIG. 5 is a cross-sectional view of a preferred display showing onearrangement where the droplets change their shape so as to function aslenses.

FIG. 6 is a cross-sectional view of a preferred display system whichutilizes differently-coloured droplets.

FIG. 7 is a top view of the display system shown in FIG. 6.

FIG. 8 is a top view of another preferred display system which utilizesdroplets of different colours.

FIGS. 9(a)-(c) are cross-sectional views of a preferred display systemin which the shape of the droplet shown, which is located on ahydrophobic polymer surface incorporating different wettability levels,is modified (and thus its optical properties are changed) by theapplication of electrical potential to one or more adjacent electrodeselectrically insulated from the droplet.

FIG. 10 is a cross-sectional view of a preferred display in which the ahydrophobic polymer layer incorporates areas of variabledroplet-repelling capabilities; and the droplets are caused to becontrollably moved in respect of different adjacent colour filters bychanges in the electrical potential present at different points on aresistant electrode adjacent to, but insulated from, said electrode, byinducing changes in wettability of said polymer surfaces adjacent tosaid different locations across said electrode, and thereby inducing thedroplet to move.

FIG. 11 is a cross-sectional view of a preferred display utilizing alens array

FIG. 12 is a cross-sectional view of another preferred display,incorporating lens and multi-colored filter arrays with actuator means,which may be located near the transparent or translucent product outersurface of an object to dynamically change the object's surface colour.

FIG. 13 is a side view of a cellular telephone with another, alternativedisplay means incorporating lens and filter arrays with actuator meansto dynamically change the object's surface colour.

FIG. 14 is a cross-sectional view of two alternative backlit displays,suitable for obtaining a wider angle-of-view.

FIG. 15 is a side view of a lamp incorporating a preferred displaysystem.

FIGS. 16(a) and (b) are side and top views, respectively, of a lampincorporating another preferred display system.

FIGS. 17(a) and (b) are cross-sectional and bottom views, respectively,of a lamp incorporating another preferred display system.

FIG. 18 is a cross-sectional view of a preferred lenticular screenarrangement.

FIG. 19 is a top view of a preferred embodiment of the invention for useas a bottle top.

FIG. 20 is a cross-sectional view of a preferred ratcheted lenticulardisplay.

FIG. 21 is a perspective view of a preferred lenticular display in use.

FIG. 22 is a cross-sectional view of a preferred lenticular display withlimited view angles.

FIG. 23 is a cross-sectional view of another preferred lenticulardisplay with limited view angles.

FIG. 24 is cross-sectional view of a preferred lens array embodiment ofthe invention.

FIG. 25 is a top view of a preferred use of the invention in street signapplications.

FIG. 26 is perspective view of a preferred use of the invention instreet sign applications.

FIG. 27 is cross-sectional view of another preferred lens arrayembodiment of the invention.

FIG. 28 is a front view of another preferred embodiment of the inventionin use in street sign applications.

FIG. 29 is a side view of a preferred embodiment of the invention in useas a flexible keyboard.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The Electronic Controlled Movement of Transparent Insulating Dropletssuch as oil in an Electrolyte

The purpose of this invention is to induce oil droplets—or othersuitable transparent or translucent items which are affected byelectrostatic fields or charges, and/or variable electrowetting effects,and which, preferably, can function as optical lenses—to move from aposition adjacent to one coloured indicia (say, red), to a positionadjacent to a differently-coloured indicia (say, green), where theposition of said indicia enables a viewer of such said (e.g.) oildroplet to first perceive the magnified image of the red indicia throughthe oil droplet, and then, after the droplet's movement due toelectrostatic and/or/electrowetting changes to the second position, toperceive the droplet as having changed to a green colour.

In FIG. 1 we see an electrically-powered stylus being applied to thesurface of a sheet of transparent, or translucent, electricallyinsulating material such as plastic or glass, advantageously withhydrophobic polymer on its lower surface Key to FIG. 1: A Stylus BStylus tip C Transparent insulating layer D Oil droplet unaffected, orrelatively unaffected, by stylus' electric field and/orcounter-electrode-induced electrowetting changes on polymer surfaceeffect E Oil droplet affected by stylus' electric field, and/orcounter-electrode-induced electrowetting changes on polymer surface, andmoving towards position above charged (green) counter-electrode F(Optional): transparent insulating material G (Optional)(Graphicallyexaggerated) any suitable means of preventing the oil droplet's fromleaving its cell H Hydrophobic polymer layer immediately adjacentdroplets and electrolyte Electrolyte and oil droplet I Light-reflectivelayer J electrolyte K (optional) (graphically exaggerated, and notnecessarily a physical indentation in the upper face of the lower trans-parent layer)any suitable surface of variable wetting properties, or ofvarying physical shape, which serves to impede (or enhance)the departureof droplets from their position(s)adjacent to colour filter means W—WElectrical pulse in cyclical addressing system YY&ZZ Lines representingthe extreme right and left-hand positions to which droplet E can move

In the particular arrangement shown above, which is only one of a numberof possible arrangements for exploiting the same principle, there is asuitable electrolyte between the upper and lower transparent sheets, andwithin the electrolyte are shown two oil droplets.

Below the lower transparent and electrically insulating layer ofhydrophobic polymer are shown counter-electrodes represented byrectangles with ‘red’ ‘green’ or ‘blue’ written within, with allsame-coloured electrodes electrically linked to a suitable electricalpower supply so that the potential is (preferably in many approaches,but not necessarily) cycled alternatively through the three colours, oneat a time.

There is a hydrophobic polymer layer (‘H’) applied to the upper surfaceof the lower transparent sheet, or the lower transparent sheet willitself be a hydrophobic polymer layer. The lower face of the uppertransparent sheet may also be hydrophobic polymer. Thecounter-electrodes and colour filters are so arranged that the colourfilters will be visible from in front (i.e., above, in the abovediagram) of the screen display means when a transparent oil dropletmagnifies a particular coloured indicia or colour filter by locatingitself above said colour filter. Thus, for example, the colours red,green and blue respectively may be positioned in front of theirrespective and corresponding counter-electrodes. Another possiblearrangement would be that each counter-electrode surrounds each colourfilter. A light reflector will also be provided behind the colouredindicia or filter if the display system is to be lit from the front,e.g., using ambient light.

There will be provided a suitable switch means on-board, or associatedwith, the stylus (to change the displayed colour where the stylus tippoints) which will energise the stylus tip with a suitable electricalcharge (or series of charges, preferably in sync with any cycledcharging of the ‘target colour’ counter-electrode) of suitable polarityat preferably the same time as one or more counter-electrodes adjacentto the ‘target colour’ (i.e., the colour that the user wishes to ‘write’in at that time) is/are energised. The stylus will be electricallyconnected to the display means—for example, by an electricallyconductive wire.

The ‘synchronisation’ of the application of suitable electricalpotential to both the stylus tip and the counter-electrode(s) associatedwith the ‘target colour’ can be achieved by any suitable means, such asmicroprocessor control of both items' power supplies.

In the above exampled illustration, a positive electrostatic field isdelivered by the stylus tip, and a corresponding negative-poledelectrical potential is simultaneously or near-simultaneously applied toone or more of the counter-electrodes adjacent to, or associated with,colour filters of the targeted colour proximate to the position of thestylus tip. As a result of the positively-charged electrostatic fieldgenerated by the stylus tip together with the charged counterelectrode(s), the oil droplet will be induce to move to locate itselfabove the counter electrode which is currently charged due to thehydrophobic properties of the polymer surface adjacent to said chargedcounter-electrode becoming hydrophilic: the image of the colouredindicia, or light filter, will be magnified by the oil droplet, whichwill function as a lens, and the observer will consequently observe thisparticular ‘cell’ in the display matrix as being of that colour.

Notes on the Above Approach, and Alternative Possible Arrangements Usingthe Same Principles

The stylus tip delivering the potential may be electrically insulated.

In an alternative approach, the hydrophobic layer on the underside ofthe upper transparent sheet of material may be removed, and instead thesurface of the upper transparent sheet of material in contact with theelectrolyte may be at any suitable position on a scale betweenhydrophilic and hydrophobic. In any event, in this light-reflectingversion (see light transmissive version, below) a light-reflectivesurface should preferably be provided behind the colour filters, or thecoloured indicia should themselves be sufficiently reflective to providegood brightness in ambient light conditions.

The indentations shown as ‘K’ on the above diagram may not necessarilybe physical indentations: they may alternatively represent a wettingdifference on the surface. These wetting differences, or physicalindentations, may serve to retain the oil drops in their desiredlocation by creating a physical or wetting resistance to their changingtheir positions. Such differential wetting surfaces, or physicalindentations, may in optional approaches be also used on the undersideof the upper transparent sheet of material.

The said ‘oil droplets’ need not necessarily be oil: they mayalternatively be any suitable non-polar liquid.

The lower ‘transparent sheet’ need not necessarily be present, providedthat there is a hydrophobic polymer layer present between thecounter-electrodes and the electrolyte.

Although only three different colours (and corresponding electrodes) areshown in the diagram, there may, clearly, be any suitable number ofdifferent electrodes with corresponding different coloured filters.Alternatively, there may be two or more address lines leading to eachcounter-electrode, so that a variable potential may be present atdifferent points along the resistant counter-electrodes, with a range ofdifferently-coloured filters or indicia positioned above it or adjacentto it. In suchlike arrangements, any suitable means of inhibiting thedroplet's movement on the polymer surface to above or adjacent to thehighest-potential sector(s) of the resistant electrode may beprovided—e.g., treatment of the polymer surface to achieve highersurface tension, or differing wetting properties—so that the droplet mayonly reach certain points or areas along the polymer when sufficientlyhigh electrical potential is delivered to the resistant electrode areaimmediately adjacent to it. This ‘variable electrical potential acrossan electrode’ technique is applicable to the other droplet-movingdesigns and approaches described herein which employ electrowettingeffects to achieve droplet movement.

In addition to coloured indicia or light filters, there may preferablybe a ‘white’ or ‘neutral’ colour filter or indicia, to above which theoil droplets would be switched if they are ‘erased’ by any suitableelectronic ‘erasing’ method. One method of electronically erasing thecolours ‘drawn’ on the screen would be to provide a separate tool inaddition to the stylus, which would attract the oil droplets to lieabove the white indicia or filter—thereby allowing the screen to appear‘clean’. Such an eraser would preferably have a larger contact ornear-contact area with the screen than the stylus tip, in order to allowfor speedier removal of the ‘drawn’ material on the screen. Optionally,of course, the eraser and the stylus could be combined into one unit. Insystems employing a row and column or other suitable address systemcapable of addressing individual or groups of ‘cells’, then all cellscould alternatively be near-simultaneously turned a suitable neutralcolour by the microprocessor without the need for a stylus-style eraser.

There are many different possible arrangements of the counter-electrodesand their address lines, both to provide different numbers of possiblecolours, and to reduce manufacturing cost by, for example, arranging forall the counter-electrodes to be positioned on the same substrateunderneath the lower hydrophobic polymer layer. One of the advantages ofthe approach we are currently discussing is that there is notnecessarily any need to separately address each ‘cell’ (i.e., eacharrangement of counter-electrodes and corresponding colour filtersadjacent to each oil drop): all the greens, for example, can beoptionally be linked together, as can each of the other sets ofsimilarly-coloured counter-electrodes. The reason for this is that insuitable addressing arrangements with appropriate electrical potentialsapplied, the counter-electrodes may only have a movement-inducing effectupon droplets when the stylus is located above or close to saiddroplets.

Thus, in the particular addressing approach shown, there may be no needfor row and column addressing. As an example of one possible physicallayout of the colour filters, the Red, Green and Blue counter-electrodescould be arranged as though they were three equal portions of a piechart on the same plane with insulation or a gap in between them: the‘same-colour’ portions of each counter-electrode set could be run sothat there was no need for insulating layers between thedifferently-coloured lines—at least, until the lines reached the edge ofthe array.

In such an arrangement, it would be possible to place a white area atthe centre of the circular counter-electrode array, for example, so thatby powering all three counter-electrodes, the oil drop could be inducedto stay in the middle of the circle, and display a white/neutral colour.Similarly, of course, applying different potentials to different counterelectrodes in a suitably-configured arrangement would provide the meansof employing a colour wheel—whereby the drop could be steered toprecisely the colour that was desired.

Whilst powering the differently-coloured sets of counter-electrodes bycycling through them has been mentioned, clearly they may be addressedin any other suitable way—e.g., continuing to apply an appropriatepotential to counter electrodes associated with one ‘colour-set’ until asuitable electronic feedback circuit confirms the target oil drop(s)has/have arrived at their target destinations, for example, or applyinga potential to one or more counter-electrodes for a specified time toallow the droplet to reach a position adjacent to the target colour.

Optionally, an electrode connected directly into the electrolyte may beprovided, with an electrical potential opposite to that applied to thecounter-electrodes, for example, for such purposes as causing thedroplets to flatten their shapes (an electrowetting effect) so as, forexample, to (a) enhance their lens-like properties and/or (b) to impedeany tendency to move from their assigned locations. Anappropriately-polarised charge to the electrolyte could optionally alsobe used to clear the display, where suitable addressing arrangements aremade.

The surface of the polymer layer in this or other droplet-moving designsdescribed herein may optionally be treated with any suitable surfacepattern—whether by deposition or other means—to achieve higher and/orlower surface tensions at different points or sectors on the polymer.Alternatively, higher and lower, or specifically-shaped, differingphysical levels of the upper and/or lower of the two sheets of materialshown (i.e., the underside of the top screen layer, and the lowerpolymer layer) may be provided, so as to impede or enhance the droplets'inclination to position itself at certain points on said surface, or toachieve specific optical effects such as inducing the droplets to have asuitably curved surface at their top sides so that they can function, orbetter function, as an optical lens to direct light onto the selectedcolour filter(s).

Such techniques may, for example, be used to impede a droplet's movementaway from its assigned location until a suitably high electricalpotential is applied to an adjacent electrode to induce it to move—by,for example, changing the wetting properties applying to said droplet atthe polymer surface so that certain locations along the surface becomemore or less hydrophobic or hydrophilic, thereby inducing the droplet tomove accordingly. In other droplet-displacing display systems (seebelow) where the droplet(s) are electrically-charged and electrowettingchanges are important, similar such ‘droplet movement-impeding’ meansmay also be used.

Use of the Above System Without a Stylus

If a stylus is not to be incorporated in the above system, then clearlyan alternative addressing system is required. Instead of the stylusdelivering an electrical potential opposite to that of the chargedcounter-electrode(s), that oppositely-poled potential would instead bedelivered into contact with the electrolyte or alternatively immediatelyadjacent to said electrolyte, but electrically insulated from it, withany one of numerous well-established addressing methods used to applypotential to selected counter-electrodes.

The Controllable Movement of Polar Droplets in an ElectricallyInsulating Liquid to Effect Perceived Colour Change at Different ‘Cells’

A somewhat similar approach to that shown above can alternatively beused, whereby instead of an insulating liquid such as oil being used forthe droplets with an electrolyte surrounding them, the droplets areinstead made up of polar liquid, and the surrounding liquid is anelectrical insulator, such as silicone oil.

Referring to FIG. 2, the electrodes associated with each colour—ormultiple colours—in each ‘cell’ are preferably separately addressed witha suitable electrical potential, thereby inducing a change in thehydrophobic polymer surface immediately above it to cause it to becomehydrophilic, and to induce the droplet to move towards a positionadjacent to said charged electrode.

If a stylus is employed in this system, it will preferably provide theground plane function. It is the differential between the electricalpotential existing between the stylus and the colour-associatedelectrodes beneath the stylus that induces the droplet to be moved as aresult of local hydrophobic/hydrophilic properties affecting the dropleton the polymer surface.

When one or more particular electrode(s) is/are charged with a suitableelectrical potential to induce hydrophilic and/or hydrophobic effectsupon adjacent droplet(s), other adjacent electrodes may remainuncharged, or, optionally they may be induced with a potential toenhance the droplet's movement to the desired location. The potentialand/or polarity applied to the stylus may be varied dynamically in somedesign approaches, according to the particular different addressingsystems employed. Clearly, the droplet can be ‘passed’ from electrode toelectrode in a stepping manner—for example, to cause it to progressivelymove to its ultimate target colour.

Although only one address line is shown in FIG. 2 leading to eachcolour, other alternative addressing systems will be discussed belowwhich could also be used.

Non-stylus—i.e., Colour Display Screen—Version using the Above Approach

If a stylus is not to be used in a system such as that shown above(i.e., if the system is to be used as a colour display means without astylus to participate in the addressing functions), then the lowersurface of the upper transparent sheet can, optionally, be madeelectrically conductive—e.g., using ITO sputtering to make it conductiveand transparent, or as another of a number of possible arrangements, anarrangement of non-transparent conductive material that does notunacceptably obstruct light paths can be provided—so that it performsthe function of the ground plane.

Many possible alternative well-established addressing systems can beused for such an approach, including those where a continuous groundplane is used above the droplet(s), with address lines below to eachcell or groups of cells, or to particular colour-associated electrodes(or portions of resistant electrodes) within each cell; alternatively,for example, a row and column system can be used—for example where therows are carried along the top sheet, and the columns along thebottom—and so on. In some approaches, transistors and/or diodes areemployed to achieve variable potential addressing of different cells.

An alternative approach is to provide a polar material, or electrolyte,above (in respect of the above diagram) the polar liquid droplets andtheir surrounding electrically-insulating liquid. Such an electrolytemay be deposited onto the lower surface of the upper transparent sheetof material (i.e., which form the viewing screen of the display system);alternatively, for example, the electrolyte or polar liquid could ‘rideabove’ (due to lower density) the droplets and surrounding insulator.Clearly in such an approach (as is usually the case in all systemsdescribed in this document where more than one liquid element is presentin the same reservoir) the respective liquids would have to beimmiscible. An appropriate means could to be made to prevent the polarliquid droplets from contacting the electrolyte or polar liquid, and asuitable electrical potential would be connected to said polar liquid toallow it to function as a ‘ground plane’. Optionally, said electrolyte,or conductive material, if deposited on the lower face of the uppertransparent sheet, could be divided into separately-addressable sectorsinsulated from each other.

The Controlled Movement of Electrically-Charged Droplets in Respect ofColour Filters

Another alternative approach to achieving theelectronically-controllable movement of liquid droplets is achieved byinducing an electrical charge into a droplet. A surface surfactant, forexample, can be used to enable an oil drop within a liquid electrolyteto retain a charge of suitable polarity, by inducing differently-poledcharges at each end of molecules surrounding the droplet, therebypresenting a consistently-poled exterior surface to said droplet.

Alternatively, conductive material can be added to retain the chargewithin an insulating liquid droplet where the outer surfaces of saiddroplet are electrically insulating, or where the liquid surrounding thedroplet is itself electrically insulating.

Alternatively, two different immiscible liquid insulators may be used,the one which is carrying an electrical charge being transparent if itis to function as a lens, and being permanently-coloured if it is tofunction within a system where different droplets pass in front of lightpaths so as to change the colour of the light (see below) passingthrough said droplets.

A further alternative is to induce a charge in a polar liquid surroundedby an insulator material or liquid.

As used in this document, “droplets” may refer to not just to liquiddroplets, but also to any kind of particles, provided that the particlesmay perform a light-refracting or light-reflecting function, andprovided that an electrowetting effect is not critical to thefunctionality of the ‘droplet-moving’ design. Such particles might, forexample, bear one or more different colours on their surface(s), so thatby reorienting themselves in respect of light paths, they causedifferent colours to be displayed when differently-poled charges areapplied, as described herein.

In any of these approaches, the electrodes, or series of electrodes,will preferably be suitably individually-addressable, and will beinduced with an electrical potential of opposite polarity to that of thecharged droplets when the objective is to attract said droplets to moveadjacent to said electrodes; and, conversely, where the objective is torepel said droplet(s), then the polarity of the charge delivered to saidelectrodes would be similar to that of the targeted droplet(s).

FIG. 3 shows one way in which a droplet may be attracted towards, and/orrepelled from, different colour-associated electrodes: the actualcomposition of the droplet and/or the liquid surrounding it would dependupon which of the above-described approaches to retaining an electricalcharge of a particular polarity is employed. At least the bottom layer,and preferably also the top layer adjacent to the insulating liquidshown in the diagram will be electrically insulating in any of thedifferent approaches. As mentioned before, although individual addresslines are shown leading to the different colour-associated electrodes,other addressing approaches may be used, some of which are discussedherein.

Clearly, regardless of which of the design approaches described above isemployed, the essential point is that by changing the polarity and/orpotential delivered to the different electrodes, the droplet can beattracted and/or repelled so as to position itself above whatever colouris currently desired. As with the other Figures, the fact that onlythree different colours are represented does not limit it to such arange: there may be only two colours, or there may be any other numberthat are desired, provided that the addressing and control means ofattracting/repelling the droplet is able to induce it to position itselfappropriately to focus light onto or through said colours.

It should be pointed out here that though the use ofelectrically-charged droplets acting as lenses or light reflectors tocause light to be selectively directed onto target colour(s) is shown inthe context of liquid droplets within other liquids, the claims of thispatent application include the use of such charged droplets where saiddroplet(s) are not surrounded by a liquid, but instead any suitable gas,including air, or a vacuum.

Backlit, or Side-Lit Alternative Versions of Droplet-Moving DisplaySystems

In an alternative embodiment to those shown thus far—which employlight-reflective surfaces underneath the movable droplets, backlightingcan be instead be provided, which can focus or direct light throughdroplets serving as lenses (or indeed in alternative approaches canobstruct light from passing) onto selected colour filters, which in suchcases may lie above said droplets.

In one embodiment shown in FIG. 4, the primary difference in the designwould be that the reflective surface provided in the front-lit designs,which is located behind the colour filters or coloured visual indicia,would be removed, and the colour filters would be located on the side ofthe oil droplets which is opposite the light source.

The light passing from the backlighting source would pass, in the caseof each cell, through the droplet, which would focus the light onto oneof other (or a combination of) the light filters appropriately locatedabove or adjacent to the oil droplet in each cell. Having passed throughthe targeted colour filter(s), that cell, or droplet, would be perceivedby the human viewer of the cell (or display screen composed of cells) asbeing of the colour of the filter(s) through which the light had passed.One suitable possible location for the colour filter array would be onor within the top sheet of transparent material.

This arrangement is applicable not only to droplet-moving,stylus-employing screen systems, but also to any screen display systemconforming with any of the liquid droplet design approaches describedherein. All such approaches require appropriate light passages from thebacklighting means through to the point at which the light emerges fromthe screen at the top of the system.

Optionally, optical lenses may be suitably positioned above and/or belowany backlit droplet or particle-moving display using approachesexplained in this document, so as, for example, to better focus lightonto or through droplets, or to distribute the image or colour of adroplet over a large portion of the front display screen.

FIG. 4 illustrates this approach: where the term ‘electrolyte orinsulating liquid’ is used, the ‘insulator’ option applies to adifferent approach, outlined elsewhere herein, where a polar liquiddroplet is used, surrounded by an insulator. Other design approaches arealso described in this document where this backlit approach could beused—for example, where the droplet is permanently electrically charged.

With a side-lit system, the upper surface (in FIG. 4) of the lightcarrying means (e.g., an internally-light-reflecting device) could bedesigned to allow light to escape upwards—i.e., through the dropletstowards the colour-bearing indicia or filters.

The above approach can be applied to any suitable designs describedwithin this document.

Modification of Droplet Shape to Provide, or Enhance the Droplet withLens-Like Optical Properties

Regardless of which of the droplet-moving design approaches described inthis document is employed, there may be occasions where a lens-likeperformance is required of a droplet so as to focus light onto one ormore particular colour filters or indicia, but where a curved top cannotbe provided to the droplet so as to allow it to adequately perform thelens function—due, for example, to the upper layer of material adjacentto the electrolyte or insulating liquid (as appropriate to each system)preventing the droplet from forming an adequately and suitably curvedsurface so as to function as a lens.

FIG. 5 illustrates one possible solution to such a problem: here we seea droplet located in a different type of liquid (as appropriate to theparticular system employed) which is in a reservoir delimited by twosheets of material, as elsewhere described herein. The colour filterswith their respective corresponding electrodes are shown below thedroplet.

It will be appreciated that in the particular example shown below, whichincludes a light-reflective layer below the colour filters, providedthat the refractive index of the droplet is sufficiently greater thanthe refractive index of the upper sheet of transparent material, thedroplet will function as a lens. The particular respective refractiveindexes, and the curvature of the ‘dome’-shaped ‘dimple’ in the lowerface of the upper transparent sheet of material, will be determined soas to focus light coming from above (in the example shown in FIG. 5)onto the targeted coloured light filter. If the droplet in FIG. 5 isinduced by potential being applied to one or more appropriately-locatedelectrodes to move towards the adjacent dome-shaped indentation to itsright, then clearly it will compress its shape to some extent to do so,and will then regain some vertical height as it re-shapes itself toconform with the dome-shaped indentation into which it moves.

It should be pointed out here that the lower surface of the upper sheetof transparent material may be optionally be non-hydrophobic, or may behydrophilic.

Further, because FIG. 5 is drawn to be ‘generic’, and not specific toany of the different droplet-moving methods described herein, details ofthe locations of electrodes and counter electrodes, etc. are not shownin the drawing.

Clearly, the above system can be inverted if a backlit display, forexample, were used. Similarly, for certain functions, the concave ‘dome’shape shown could instead be convex if so desired, with appropriaterespective changes in the refractive index of droplet and transparentsheet being made as necessary. Optionally, such concave shaping of the,e.g., polymer surface in contact with the liquid(s) can also, oralternatively, be employed on the lower sheet of material.

The Controlled Movement of Permanently-Coloured Droplets to AchievePerceived Colour Change on a Display Screen System

It will be appreciated that similar methods to those described formoving transparent, translucent or light-reflective liquids described inthis document can also be used to move droplets which are themselvesdyed, or otherwise permanently reflect, particular different colours.

Whereas, for example, with transparent liquid drops we may have beenconcerned with positioning them so that they refract light so as tofocus it on or through particular colours amongst a variety available,with permanently-coloured liquids, by contrast, we are instead concernedwith placing droplets bearing the colour(s) we desire to be displayed tobe moved into appropriate light paths.

The use of differently-coloured droplets clearly requires a means bywhich the droplet(s) of the desired colour(s) may be addressed, andthereby caused to move into the light path(s). There are many potentialmeans by which this can be achieved, and we will only examine a briefsample here for the purposes of example.

Such approaches may include electronically-controlled display systemsfor selectively moving one or more coloured droplet(s) among more thanone coloured droplets which are joined to each other, or are attractedto each other, or are adjacent to each other, but in any approach arepreferably composed of mutually immiscible liquids, into a light path byelectrostatic means, where at least one droplet is electrically chargedwith an appropriate polarity and potential, or where at least onedroplet is addressable, and can be induced to move by any of thedroplet-moving methods described herein, by virtue of said droplet(s)being alternatively composed of polar liquid or an insulating liquid.Optionally, more than one droplet may be discretely induced to moveitself, by any combination of the droplet-moving methods describedherein, or more than one droplet may have the same droplet-moving methodapplied to it, where it and its environment accord with the methodsdescribed herein to move droplets.

FIG. 6 illustrates one such implementation of the above approach: thethree droplets shown, which may be assumed for example to be green, redand yellow (from left to right) are joined together by any suitablemeans, or are permanently attracted to each other. In FIG. 6 only onecoloured droplet—the yellow one on the right—bears an electric charge:the other droplets do not, and may, for example, be of non-polar, orinsulating, material. All 3 droplets and any insulator in which they arelocated, are preferably mutually immiscible.

Top and bottom sheets of material shown adjacent to the droplets may betaken to be transparent or non-transparent insulators—though in certaindesign approaches the top sheet could be conductive Towards the bottomright and top right there are shown two sheets of transparent material,which function as windows to permit light through.

Sets of electrodes (the term sets is used because they appear to beseparate, though, in fact, they may be one conductive item), circular inshape with a hole in the centre to allow light to pass through, are alsoshown. It will be appreciated that when an appropriate negatively-poledpotential is applied to set A electrodes, if the yellow droplet were notalready present in the light path, it would have been induced to moveinto it If instead Set B of electrodes is now charged with a suitablenegatively-poled potential, the yellow (right-hand) droplet would moveto reposition itself to the right of its currently-shownposition—thereby dragging the red and green droplets after it, andpositioning the red (middle) droplet in the light path—thereby changingthe light passing through the ‘windows’ from yellow to red in colour.

Only two ‘sets’ of electrodes are shown in the diagram: clearly, inorder to be able to move green into position, a further set would inmost arrangements be required, ideally negatively charged, to the rightof set B of electrodes. In order to move the ‘train’ of coloureddroplets back again to the left, the electrodes would be pulsedappropriately one-by-one.

If potential of polarity similar to that of the charged droplet isapplied to one or more electrodes, then the repelling force therebygenerated can also, or alternatively, be used to achieve droplet motion.

If desired, more than one droplet may be permanently charged—either withthe same polarity, or with different polarities of electrical charge,depending upon the appropriate arrangement of pulsing the electrodeswith appropriate polarity and potential.

Instead of backlighting the system as shown above, a reflective surfacecould instead be located where the lower transparent ‘window’ is shown.

An alternative arrangement would incorporate one or more optical lenses,suitably-positioned and configured so as to magnify the image and/orcolour of the ‘targeted’ coloured droplet. If the system werelight-reflective, this lens arrangement could for example be locatedabove the target droplet, with a reflective layer underneath thedroplet. Said reflective layer may optionally be curved.

If, alternatively, a light source were provided for backlighting, thenof course the reflective layer would be removed, and appropriate lens orlenses located so as to ‘fill’ the cell area at the screen front withlight of the colour of the illuminated droplet. Additional lenses mayoptionally be used in such arrangement to direct the light towards thelocation where the target coloured droplet is located.

FIG. 7 shows one optional arrangement whereby said coloured dropletscould be prevented from escaping from the area within which they arefree to move. The wetting, or surface tension, properties of the centreand outer area are such that the droplets would be repelled from them,and would instead be induced to remain in the central area. Positions ofelectrodes, etc. are not shown in this drawing for purposes of clarity.

As shown in FIG. 8, another alternative layout has the advantage thatthere does not need to be a means by which the immiscible liquiddroplets are attached to each other, or are joined to each other FIG. 8shows a number of differently-coloured liquid droplets. In thisparticular example, only one of them is electrically-charged with acertain polarity.

The drawing also illustrates how other droplets could alternatively, orin addition, be composed of appropriate liquids as disclosed elsewherein this document as alternative means of moving droplets. Clearly, theappropriate liquid and addressing methods appropriate to each of thedifferent said droplet-moving methods would be supplied to make theselected system work.

Preferably, underneath the currently-shown location of each droplet is aseparately-addressable electrode. By applying potential to eachelectrode in turn, the charged droplet can be pushed or manoeuvredaround the ring—forcing the other droplets to move with it.Alternatively, as described elsewhere herein, one or more resistantelectrodes could be located adjacent to one or more positions of the‘ring’ shown, and appropriate potential delivered to the differentaddress lines connected to said resistant electrode would cause affecteddroplet(s) to change their positions accordingly.

The above approach can be applied to the other methods by which coloureddroplets are moved into a light path. The droplets, again, cannot escapetheir ‘race track’ due to the repelling properties of the wettingsurface on each side of each droplet, towards the centre and towards theoutside. Such properties can, conveniently, be deposited onto thesurface upon which the droplets are located by printing or othersuitable means. Alternatively, any other suitable means of delimitingthe locations where the droplets can move to can be provided. Dependingupon the material from which the droplets are made, they may bedepositable by such techniques as ink jet printing.

A Similar Approach using Permanently-Coloured Polar Liquid DropletDriven by Local (Insulated) Electrodes' Electrical Potential Instead ofOne or More Permanently-Charged Droplet(s)

A very similar approach can be used where droplet(s) of polar liquid areattracted towards, or repelled from, locations on a hydrophobic polymersurface adjacent to one or more appropriate-charged electrodes, with aground plane on the other side of the system, as explained herein.

Just as in the coloured droplet approach above, one or more droplets ofpolarised liquid may be used, where said droplet(s) is/are located in anelectrically insulating liquid, and other differently-coloured dropletsmay be composed of any suitable liquid—for example, insulating liquidssuch as silicon, provided that each droplet will preferably remain (asabove) immiscible with the others. As newly-hydrophilic sectors of thepolymer along which the drops are located are ‘created’ by appropriateelectrical potential delivered to proximate insulated electrodes (asexplained herein), the polar liquid coloured droplet will move fromsector to sector, and the droplet currently in the path of light willcause said light to become a similar colour to said droplet.

A Similar Approach Using Oil (or Other Suitable Insulator Liquid)Droplet(s) in a Suitable Electrolyte.

The same basic approach can be used where an oil droplet is the iteminduced to move by electrowetting means, as explained elsewhere in thisdocument, and otherwise performing a similar role, together with otherliquids of appropriate composition and of different colours, asdescribed herein.

In all the above systems, lens arrangements can be made as explainedelsewhere herein, and/or reflective surfaces can be provided or absent,according to the manner of illuminating the display means.

Optionally, with any of the above coloured droplet-moving systems, aliquid immiscible with the other droplets may be used to enclose thedifferently-coloured elements so that it is, for some exterior purposesat least, a single droplet.

Differently-Poled Permanently Electrically-Charged Coloured Droplets orOther Suitable Non-Liquid Items

Using any suitable approaches described herein, droplets of liquid, orother solid charge-retaining solids, could be induced to take and/orretain a charge of opposite polarity at different points within theirshape. By changing the polarity of proximate electrodes in the mannerdescribed above, such droplets or solid items could be caused to havedifferent parts of their total area, bearing different colours, passinto and out of one or more light paths, thereby displaying differentcolours to the observer. Such approaches could include reflectivesurfaces for front-lit systems, or suitable lens arrangements forbacklit systems.

Use of any of the Colour-Changing Systems Described Herein for thePurpose of Changing the Exterior Perceived Colour of any Suitable Items.

Although the colour-changing systems described herein have been dealtwith in the context of colour display systems suitable for screens,etc., it should be pointed out that any of these inventions may alsoalternatively be used in a similar manner to change the exterior colour,or pattern of colours, on the exterior surface of any suitable items.

As an example, the colour, or pattern of colours, on the outer surfaceof a mobile phone could be changed dynamically by laying an appropriateone of the described systems along or close to its surface(s). The sameapproach could be used to change the colour(s) of innumerable othercommon-place items.

Use of any of the Colour-Changing Systems Described Herein for thePurpose of Projecting the Light of Dynamically Changeable Colour(s)

In the same way as any of the colour-changing systems (or anycombination thereof) described here are arranged, such systems may beused to project images or coloured light, or to change the colour oflight where any suitable type of light source is employed, so that saidlight source would appear to the observer to be of different colour(s)when dynamic changes to the control of different optical elements withinthe design were made. This would include using any of said systems as asimple light filter means rather than for a display screen—e.g., forplacing in front of any kind of light source—e.g., halogen, or LED, orneon, incandescent, ambient, etc. These systems could thus be employedfor such purposes as the changing of the colours of lights in interioror exterior locations, or for theatre, building, swimming pool, etc.lighting. It should be noted that the light-changing systems describedherein need not necessarily be employed in an array, but may instead beused as a single colour-changing cell arrangement.

The Use of an Additional Electrical Potential between the Stylus (inStylus-Employing Display Systems Described Herein) and One or MoreConductive Elements Underneath (in light-Reflective Systems) the LightFilters and Insulated from the Counter-Electrodes Located under thePolymer Layer.

Optionally, in the case of any of appropriate versions of thestylus-employing display systems described herein, an additionalelectrical potential may be applied between the stylus and one or moreconductive elements acting as counter electrodes which are located onthe opposite side of the screen system to that of the stylus—i.e., arelocated underneath the polymer or (where appropriate) other insulatinglayer For example, in the case of a light-reflective system, theobjective would be to enhance the forces acting on droplets beneath oradjacent to the stylus by having an electrical ‘loop’ from the stylus toone or more conductive surfaces underneath the light filters—optionally,where said conductor(s) are separately addressable. Said conductivelayers should preferably be separately addressable from, and insulatedfrom, the counter electrodes designed to attract (or repel) dropletslying in contact with the polymer or insulating layer. This additionalcounter-electrode would preferably extend across the whole screen area,and would be electrically insulated from the droplets and anyelectrolyte used.

For a similar purpose, in appropriate stylus-employing screen displaysystems described herein, an electrical charge may be delivered into theelectrolyte so as to enhance the stylus's ability to move droplets, orfor other purposes such as affecting the shape of droplets. Such acharge may be electrically connected to the electrolyte, or mayalternatively be an electrical potential delivered to one or moreconductive elements immediately proximate to the electrolyte (e.g.,adjacent to, or beneath, the top transparent screen's surface) butelectrically insulated from it.

Dynamic Control of Droplet Shape to Change its Optical Performance

The shape of a liquid droplet can be electronically induced to changeits shape, so that instead of re-positioning itself to cause light to beselectively directed onto different adjacent colours, and thereby to bedisplayed to an observer of the display system (as is described asachieved by various alternative or complementary means describedherein), in the approach introduced here, the droplet is instead inducedto change its shape, and thereby to defract (or reflect) light ontodifferently-coloured visual indicia or filters proximate to it,according to the electrical potential delivered to one or moreelectrodes located at appropriate positions proximate to said droplet.

FIGS. 9(a)-(c) show rather crudely how this may be achieved. Becausethis effect may be achieved in a number of different ways, theelectrical addressing means, and other elements of the system are notshown, as each alternative arrangement appropriate to achieving theeffects described below are described herein.

In FIGS. 9(a)-(c) a droplet of a suitable liquid (as described herein)is positioned on an electrical insulator, which will in most designapproaches be a hydrophobic polymer. Surrounding the droplet aresurfaces which are less wettable than the areas surrounding them whenthe adjacent electrode is charged, or are, due to any other suitabledesign feature relatively repellent to droplets moving onto them thanare the other adjacent surface areas

These surfaces may for example, be permanently treated so as to be ofsufficiently high surface tension to repel or prevent the droplet frommoving above them, even when electrical potential is applied to localelectrodes, thereby inducing said droplet to be attracted to move topositions above or immediately adjacent to said charged electrode(s).

These areas may alternatively function so as to be, or to become, lesshydrophilic—when adjacent electrodes are suitably charged with anelectrical potential so as to change the hydrophobic/hydrophilicproperties existing at polymer surfaces proximate to saidelectrode(s)—than other surfaces adjacent to the droplet, therebycausing the droplet to be more attracted to the more hydrophilic areas.

Two separately-addressable electrodes, located underneath the insulatinglayer, are also shown. A multi-coloured filter array is shown locatedbeneath the droplet.

In FIG. 9(a) no electrical potential is applied to eitherlocally-positioned electrodes.

In FIG. 9(b) a potential has been applied to the right-hand electrode,so as to induce the droplet to move towards that charged electrode. Thedroplet, for example, may be positively charged, and the electrode inquestion may be receiving a negative charge of suitable potential so asto attract the droplet. In this case, there are conflicting forcesacting on the droplet: the differently-poled influence as against thedroplet-repelling forces induced by less wettable surfaces existing atthe red-marked zone partly above the currently-charged droplet.Alternatively, the droplet may be a polar liquid located in aninsulating liquid (surrounding liquids, and other elements of thesystem, are not shown here): the ‘less wettable’ areas of the polymerlayer (shown) are sufficiently repellent to the droplet that its surfaceangle to the polymer plane becomes steep, and the droplet presents anoptical profile which is higher on that side than on the other.

With appropriate electrical potential delivered to the currently-chargedelectrode, and with suitably less wettable or unwettable surfaces at theindicated surfaces, it will be appreciated that the droplet may becaused to become more or less bulbous at its right-hand side incomparison with its left-hand side. As a consequence of this, it willdefract light passing onto or through it in different ways according toits shape. In FIGS. 9(a)-(c), where coloured filters are located belowthe droplet, different colours may thereby be reflected (in the case ofa reflective display) or transmitted in an (e.g.) backlit display to beaccordingly displayed to the observer of such a system as a colourchange at this point.

It will be further appreciated that while FIGS. 9(a)-(c) are of acertain configuration to allow light to pass onto or through certaindifferently-coloured filters, the same basic approach may be used formany other applications where the droplet may reflect light ontodifferent colours due to its changing shape, or where the droplet may asa result of its changing shape modulate light passing through, orreflecting off it, so as to function as a switch means enablingdifferent amounts of light, or different frequencies of light, to passthrough or reflect off it.

In respect of colour-changing systems for display purposes, any suitablemeans associated with droplet-moving systems described herein may beapplied to distort droplet shape. The droplet, therefore, may be a polarliquid located within an insulating liquid, for example, or it may be aninsulator located in an electrolyte liquid, and so on. If electrowettingforces are causing the droplet to be induced to move in the aboveexample to the right, then clearly the arrangement would include meansto cause the surface shown as red rectangles to be less hydrophilic, orindeed to be hydrophobic, when the charge is applied to the electrodeadjacent to said indicated rectangles in the drawing at the polymersurface.

In FIG. 9(c) the left-hand electrode has been charged with a suitableelectrical potential, and the right-hand electrode is no longer charged.We see that now some light reaching the droplet is focussed onto adifferent area of the coloured light filter array.

For other desired optical or other effects, multiple electrodesaffecting the forces acting on a droplet, such as those shown above, forexample, may be simultaneously be charged with suitable electricalpotentials.

It should be noted that the methods described for delimiting, orrestraining or modifying, the movement of droplets to various differentlocations may also be used in any other appropriate optical system,including those described elsewhere in this document.

Optionally, a high surface-tension means of preventing the droplet frommoving above designated locations beyond its surface perimeter area maybe replaced with any other alternative means which prevent or lessen theforces inclining the droplet to move to locate itself above, or to aparticular location in respect of, charged electrodes. Thus, as anexample, the surface upon which the droplet is moving may be raised upor lowered down to increase or reduce the effect of the chargedelectrode on the droplet.

It should be noted that the above diagram and explanation is given onthe basis that the droplet is attracted to move to place itself closerto an electrode (or closer to a polymer area whose surface has becomehydrophilic). The same basic approach may alternatively be used wherethe forces acting on the droplet cause it to be repelled from a certainposition, but where delimiting elements in the design prevent it fromfully moving to certain locations, so that the droplet shape distortsinto one where the angle of the droplet in respect of the surface uponwhich it is located is different at different points around theperimeter of the droplet.

The application of heat to the interface area between droplets and thearea of polymer surface in contact with them so to reduce the surfacetension of the effected droplet(s)- and thereby to affect its/theirsusceptibility to locally-induced forces (e.g., electrowettinginfluences) affecting them which in the absence of said locally-appliedheat would be insufficient to cause said droplet(s) to change its/theircurrent position but in the presence of sufficiently-increasedheat-inducing means at the droplet-polymer surface interface will causesaid droplet(s) to charge their position along the polymer surface inrespect of differently-coloured light filters or light reflectors.

The surface tension of droplets can be affected by temperature changesinduced in the interface between the droplet and the hydrophobic polymersurface with which they are in contact. This provides a potentiallyuseful means of causing one or more ‘targeted’ droplets in a visualdisplay system, which are proximate to a suitably-equipped stylus, to bemore, or less, affected by any local electrowetting influences inducedby adjacent insulated electrodes. Thus, as an example, if—as isdescribed elsewhere in this document—a droplet of polar liquid in aninsulating liquid is attracted to move towards a suitably chargedelectrode adjacent to it but insulated from it, where for example aground plane is located above, but insulated from, said droplet, theapplication of a temperature increases to said droplet-polymer surfaceinterface could be used to enhance said droplet's tendency to move alongthe polymer surface adjacent to it towards the currently-chargedelectrode, caused by said surface becoming hydrophilic.

As just one example of how an induced temperature change in said dropletto affect its surface tension could be useful in the above example,consider the case where complex addressing systems would otherwise benecessary in the display system—that might, for example, require moreaddressing lines than desired, or might require the use of suchcomponents as diodes or transistors at each ‘cell’ to allow appropriatepotentials to be delivered to the ‘target’ cell as well as to othercells in a display system so as to cause a change of location in onlythe targeted droplet: in such a case, if the local presence of thestylus changes, via the employment of a suitable electrically-poweredarrangement, the temperature of said droplet so as to cause it to be theonly droplet in the display system where the balance of forces inducingit to change position are greater than those inducing it to retain itsposition, then clearly the employment of such an approach couldfacilitate the use of a much more simple address system.

As a more specific example, consider the situation where the electrodethat is currently charged to induce the droplet to move along thepolymer layer towards it due to hydrophilic properties being inducedalong the polymer layer local to said electrode—that said electrode isconnected to a row-and-column address system arranged so that dropletsalong the same row and column as the targeted droplet will be also besubjected to forces tending to move all or some of them from theircurrent position.

In such a case, if the heating of the targeted droplet(s), achieved byany suitable means which is induced only on one or more (as desired)droplets immediately proximate to the stylus tip, then the change insurface tension induced by temperature change of said droplet(s) will besufficient to change their resistance to changing their position—orexpressed differently, will serve to increase the balance of forcesacting on them change their position—and as a result, said targeteddroplet(s) will move towards the adjacent area of greater hydrophilicproperties, whereas other droplets in the display (in this example,other droplets along the charged row and column) will not move, becausetheir surface tension properties at that time are such that said balanceof forces acting on them is insufficient to cause them to changeposition.

Any suitable means can be employed to cause droplets adjacent orproximate to the stylus tip to become hotter when switch meansassociated with the stylus is set to cause such an effect. The stylus,for example, might in its tip incorporate heating means; or it mightincorporate any suitable other energy-generating means—e.g., a laser orultrasonic emissions—which directed towards and focussed on the surfaceunderneath droplets adjacent to the stylus within the screen system,thereby cause them to heat up. The system might incorporate means bywhich the current position of the stylus can be ascertained, and inaddition incorporate a suitable addressing means to direct electricalpotential to conductive elements proximate to the droplets adjacent tothe stylus tip to be energised and thereby rise in temperature; anyother Ohmic heating technique might be used—and so on. There are almostinnumerable means of causing the droplet-surface interface(s) proximateto the stylus tip to be heated up: the important point here is that anysuitable means of doing so may be employed.

Employment of Variable Surface Tension, or Wettability, Properties on anInsulating Surface to Modify the Behaviour of Droplets

It will be appreciated from the above description that permanenttreatment can be made to insulating surfaces so that droplets in asuitably-configured droplet-moving display system can be inhibited, orinduced, to move to locations of different wettability in the presenceof one or more appropriately-charged electrodes proximate to, butinsulated from, said droplets.

Such variable wetting surfaces along an insulating surface can be usedfor a number of purposes other than those described elsewhere in thisdocument.

One application is to introduce variable wetting along a surface that adroplet may move as a result of different potentials being applied toone or more electrodes insulated from, but proximate to, said surface.For example, if a droplet is free to move along, e.g., an insulatinghydrophobic polymer surface underneath which there are three differentelectrodes with associated and respective different-coloured lightfilters, it may be useful to locate areas of less wettability (even whenelectrodes are charged) between the areas of the polymer surfaceimmediately adjacent to the electrodes, so that, for example, thedroplet will, if sufficient forces are acting upon it, overcome one such‘less wettable area’ in order to move to the next—and may thereby causea different colour to be displayed. The forces acting on it at this newlocation, however, may be insufficient to enable it to either overcomethe less wettable ‘barrier’ it has just crossed, or to overcome a lesswettable area separating its current position from, for example, thepolymer area further on, which is associated with a differently-colouredfilter.

Many other uses of such variable wettability patterns can be conceived:it may, for example, be desirable for a droplet to take a particularroute towards an area of higher attraction that than that where itcurrently resides: if the route is demarked with lower surface tensionas the ‘road’, and higher surface tension as the road's perimeter, thenclearly this provides a means of guiding droplets to take particularroutes to different locations along an insulating surface.

Variable Potential across a Resistant Electrode or Conductive Surfacebeing used to Selectively Induce One or More Droplets to locateThemselves at Different Locations on an Adjacent Insulator Surface inRespect of Zones of Different Values of Electrical Potential Zones onsaid Conductive Surface.

An extension of the above idea is a resistance electrode which has twoor more different electrical potentials delivered to it at differentpoints over its area—say, at different ends or sides of itsshape—causing different electrical potentials to be present at differentpoints over its area. Optionally, said electrode may incorporate areasof different electrical conductivity over its area.

Using this approach, a droplet adjacent to, but insulated from, saidresistance electrode would—in the absence of other factors and in thecontext of an appropriately-configured arrangement such as thosedescribed in this document—be induced to move to that area of the (e.g.)polymer upon which it may lie which is closest to the highest-potentialarea of said electrode.

It will be appreciated that using this approach, one or more dropletsmay be ‘steered’ from position to position on the insulator separating,but adjacent to, said variable-potential resistant conductor.

Optionally, another element can be added to the above approach: areas ofthe insulator—e.g., a hydrophobic polymer surface—may bepermanently-treated or prepared so as to have—when adjacent conductiveareas are charged (or, in optional versions, not charged) with apotential, as appropriate and desired—a higher or lower wettability, orsurface tension, than other areas.

Using this approach, for example, a droplet may be induced by potentialat a conductive area adjacent to it through the insulator, to move to acertain location, but may be contrarily impeded from doing so by ahigher surface tension, or less wettable area of the (e.g.) polymersurface which prevents it from moving to where it would otherwise go. Ifincreased electrical potential (or potential difference with, forexample, a ground plane in some systems) is delivered to proximate saidconductive area, however, the forces inducing the droplet to move closerto said conductor would eventually be greater than those repellingforces caused by the aforesaid permanent surface treatment—and thedroplet would progressively move closer to the higher-potential zone(s)of the (preferably) resistant electrode in question.

This method can be used in many ways: as just one example, ifdifferently-coloured filters are located adjacent to said insulatorsurface (such as is shown in many of the droplet-moving designs shownherein), the droplet could be induced to progressively move overdifferent coloured filters as the potential applied to the electrode—orarea of a resistant electrode—is increased.

FIG. 10 illustrates this approach, which can be used in many differentways to direct a droplet to different locations by controllably varyingthe electrical potential across, for example, the same resistantelectrode, and thereby creating different levels of forces at differentpoints over an adjacent insulating surface upon which the droplet lies.

FIG. 10 shows how any suitable means, including variable levels ofwettability or variable surface tension (or other droplet-repellingmeans), over the insulating surface permits the controlled movement ofthe droplet to different locations in respect of said resistantelectrode, by modulating the electrical potential applied to saidconductor at different points and/or, optionally, other conductorswithin the system.

Thus, in the drawing below, the potential is greatest at the left-handend of the resistant electrode, but so are the ‘droplet repelling’properties at the surface of the illustrated transparent insulator, suchas hydrophobic polymer: thus, increasing the electrical potentialapplied to the left-hand wire leading to the resistant electrode, forexample, could be expected to eventually induce the droplet to movefully to the left-hand end of the insulating layer.

Note that the use of the term “optionally, other conductors” is designedto include within this approach systems where a droplet may beelectrically charged with a certain potential—and therefore otherelectrodes are not necessarily required to induce the droplet to movetowards an oppositely-poled electrode.

This approach may be used in combination with any suitable differentdroplet-moving system in this document, or with other systems where, forexample, it is useful to be able to selectively move a droplet (or othersuitable item) to different locations by, preferably, only changing theelectrical potential applying to one resistant electrode.

Mutual Combination of Inventive Design Elements Described Herein.

Any of the embodiments, or elements within said embodiments, describedherein may be combined with any other embodiments, or elements of such,described herein, in any appropriate manner whatsoever.

Lens Arrays

The movement of lens arrays in respect of substrates or other itemsbearing multiple colours or different reflective or light passingcapabilities over their surface, (or visa versa)—is a means by which asuccession of different colours or images, for example, can be displayedor projected as the lens and/or said substrate move in respect of eachother. FIG. 11 shows one possible arrangement to provide saidfunctionality.

In FIG. 11, an arrangement of lenses above a substrate bearing multipledifferent colours is shown. A second lens—which is applicable to certainapplications, but which is optional—is shown below the substrate, tore-align the light rays reaching it. Such additional lenses may in factbe used both above and below such an arrangement, as is shown here, soas to better align light passing through them so that the light directedonto different reflective or light passing elements may be moreeffectively focussed, and/or the perceived colour of a droplet may beperceived over a larger area on the front screen.

The two two-headed arrows adjacent to the lens and filter array,respectively, indicate that one or both may be moved in respect of theother so as to change the light emerging from the system, due to ithaving passed through (or at least onto, in reflective systems)different locations on the substrate with different light absorbing orreflecting properties. Any suitable actuator means may be used for thispurpose.

Although in FIG. 11 light is shown passing through the system, inalternative versions, one or more light-reflecting surfaces will beprovided behind or underneath (in the above example) the filter array,so that having been influenced by the particular reflective orlight-absorbing item(s) onto which the lens(es) have focussed the light,it is then reflected back again.

It will be clear that there are almost innumerable potentialapplications of the above principles, where signs or displays can changetheir messages, light sources can be caused to change their emittedcolour, the colour or appearance of exterior surfaces of commonplaceitems can be dynamically changed—and so on. In this document, we shallbe looking at just a few of these potential application areas.

Dynamic Control of the Exterior Appearance—Colour etc.—of Products andOther Items

FIG. 12 illustrates just one of many possible methods of moving the lensarray vis-à-vis multi-coloured indicia-bearing or colour filter array(s)to change the outer appearance of any suitable item—a mobile phone, forexample, or a computer screen's outer case colour or pattern, etc.

The method is fundamentally the same as is illustrated above: anysuitable actuator means can cause one or more of a greater number ofpossible colours of patterns, etc, to be displayed to the viewer of anobject where a design such as that shown below is employed. Materialswhich change their shape when electrical potential is applied tothem—Piezo-electric materials, for example, bimetallic strips, shapememory polymers and other shape-memory materials—are particularlyattractive for this actuation function. Clearly, however, any suitableactuator means may be used, including manual movement—say by a knob on amobile phone, for example, to change its appearance by moving the filteror lens means in respect of each other until a design attractive to theuser appeared.

Such a design, as is shown in FIG. 12, may optionally be inverted—i.e.,with the lens array beneath the image-bearing substrate—if the device isto be illuminated from underneath. Either the lens array, or thefilter-bearing substrate, or both, may be moved.

Many of the colour-changing techniques described herein are applicableto changing the colour, or pattern, or image visible when viewing theouter surface of many everyday (and less common) items.

FIG. 13 shows a very simplified and out-of-scale illustration of theprinciple of moving a substrate bearing visual indicia behind atransparent/translucent material, which in this drawing forms the outercover of a cellular telephone, so as to enable the observer of thesurface—e.g., the cellular telephone—to observe a series ofcolour/pattern changes. Similar methods could be applied to many otherproducts or items.

In FIG. 13, lenses are shown (exaggerated many times for clarity) whichcould, advantageously, be incorporated into the surface treatment of theproduct case exterior (or interior)—e.g., into the plastic injectionmoulding of the phone.

The source of illumination may be that of one or more light sourcesoutside the product case—e.g., ambient light—or alternatively by lightsource(s) behind, or adjacent to, the image/colour-bearing substrate.Light-trapping, or ‘total internal reflection’ materials referred toherein may also be suitable in certain design approaches.

In the case of ambient light as above, there will, preferably, beprovided reflective surface(s) beneath the image/colour-bearingsubstrate.

In the case of artificial light from behind or adjacent to the lens orsubstrate, the arrangement (as shown above) may, optionally, be modifiedto more closely resemble the embodiment shown in FIG. 14.

In FIG. 14, one possible alternative arrangement to achieve surfacecolour change, in this case using back lighting, is shown. The lightpasses through the lens, then through a particular part of thefilter/image-bearing indicia carrier means, and then onto a lightscattering means. The purpose of the latter is to reduce or eliminateany problem of angle-of-view—i.e., the danger of the observer seeingdifferent colours/indicia from different angles. The scattering screen,however, although advantageous, is an optional arrangement.

Optionally, a lens (array) could be placed above the colour filter inaddition to, or instead of, the lenses shown below the filter.

The ‘separator means’ shown in the drawing could alternatively, or inaddition, be provided above the colour filter and before the screen. Theseparator means is advantageous, but optional: its purpose is to reduceor eliminate light passing through neighbouring ‘cells’ or lenses frominterfering unacceptably with each other.

Clearly, the actuator means can move either the visual indicia carriermeans, or alternatively (or in addition) the lens(es).

Optionally, florescent materials may be incorporated into the device soas to enhance the brightness of the visual indicia.

Two options which may be utilized with this embodiment include (1)irregular shaped lenses which are especially steep-sided towards theedges of the lens, so as to show the same image/colour to an observer ata wide range of different angles, and (2) lenses incorporating lightscattering means. In this option a substrate incorporating visualindicia such as different colours, or images, is positioned so as toreceive light that passes through the lens; after the light has passedthrough said substrate, it is reflected by an appropriately-shapedreflective surface, so designed as to direct the reflected light backtowards the lens in such a course that as much as possible of the lightreaches the area of the lens which is designed to function as a lightscattering device.

Some examples of products which could benefit from such acolour/pattern/image-changing means include:

-   (a) mobile phone outer cases which can change to take any one of    many possible colours, or patterns—including, of course, changing    colour/pattern in response to specific conditions—e.g., when a phone    call is received.-   (b) computers which can similarly change colour to that preferred by    the user at any particular time—or, of course, to thus change in    response to specific situations;-   (c) car sun roofs which can be automatically, or manually, adjusted    to let in the desired amount of light—e.g., in response to the level    of sunlight—or to change to a desired colour;-   (d) toys which change their appearance—for example, a red sports car    is transformed into a police car with appropriate markings;-   (e) military applications: the colour-changing methods described    could be used for such applications as changing the appearance of    military vehicles, planes, tents, combat uniforms, etc., so as to    match their surroundings with suitable camouflage patterns or    colours (using, for example, cameras to monitor their surroundings,    and then to make appropriate changes to the displayed colours);-   (f) watch faces/watch cases;-   (g) fashion accessories;-   (h) glasses frames, etc., could change to any colour or pattern.-   (i) car bodies: body panels of a car, etc., could change to the    desired colour-   (j) clothes—which can change colour/pattern.-   (k) push buttons, etc., which can change colour, or can display    different visual indicia-   (l) image/text which can appear or disappear, or change, depending    on the status and requirements.    Movement of the Lens/Lens Array on the One Hand, and/or    Indicia-Bearing or Filter or Reflecting Means on the Other, (as    Described Above), for Changing the Colour of Light Emitted by    Electrically-Powered Light Sources

The system described above can be applied in many cases to dynamicallychanging the colour of light emitted from electrically-powered lightsources—particularly those lighting methods which use a ‘point’ lightsource.

FIG. 15 shows a lamp, such as a halogen lamp. Any suitable means ofmoving the light filter means, and/or the lens array(s) will serve tochange the colour of the light emitted from this system. The additionallens array above the glass may be omitted in alternative versions ofthis design.

The actuator means can be of any suitable type: it could bemanually-actuated, for example by twisting a ring around the front ofthe lamp with a cam surface causing the lens/filter juxtaposition tochange; or it could be heat-assisted, for example, where hot airgenerated by the lamp was used—with suitably-configured fins, forexample—to produce sufficient energy to turn or otherwise move the lensor filter array: in such a case, only a means of releasing and arrestingthe motion would be required. Alternatively, of course, any othersuitable methods of actuation may be used, such as any suitable shape ordimensions-changing material which changes its shape or dimensions whendifferent electrical potentials, or different temperatures, are appliedto it, and thereby cause the required movement—and so on.

FIGS. 16(a) and (b) show another version of essentially the sameapproach. Here, some or all of the light from the light source isdirected, partly by the reflector, towards a similar lens andmulticoloured filter arrangement at the centre of the lamp front. In theexample shown, the light is reflected back towards the lamp's mainreflector; the reflective layer behind the arrays could alternatively beremoved.

Although ‘point source’ types of lighting means are particularlysuitable for the lens and filter array approach described herein,non-point lighting sources can also be employed to effect desired colourchanges. The drawing below shows one such example, which might be, forexample, a ‘Christmas tree light’.

FIGS. 17(a) and (b) show a cross-sectional and bottom view of a lamp.The details of design—actuator means, power supply, etc.—have beenomitted for purposes of clarity. In the drawing, a light source such asan electric filament, for example, is shown at the centre of the lamp.Around it is a circular lens array, which revolves, powered by anysuitable actuator means. The revolving lenses—which are in this examplevertically-oriented, to match the ‘shape’ of the light-emittingmeans—focus light from the light source onto particularly-colouredvertically-oriented ‘strips’ on the external multicoloured filter array.A small sample of possible colours arranged on the filter array is shownat ‘X’.

It will be appreciated that provided that the vertically-oriented linesor strips of particular colours are suitably arranged so that, forexample, all the red colours are equally and appropriately spaced aroundthe colour array so that light from the light source will be focussedonto all the reds at the same time, then an observer walking around thelamp would see—at the centre of the lamp, laterally-speaking at least,that the lamp was of a red colour (at least to a substantial extent). Ifdesired, the special relationship of the lenses and individually-colourfilters need not be regular, if it were intended that the lamp beperceived as a certain, same colour, throughout its area—or at least, tothe extent possible. In such a case, the position of the filters (and/orindeed the lenses) need not be regular, but could instead be at variablemutual distances, or sequence of colour order.

It will be appreciated that this approach, then, could be used to modifythe colour, or indeed the amplitude, of light generated by a non-pointsource. In the case of the Christmas tree lights, such methods asemploying the hot air generated by the lamp could be used, for example,to cause the lens array (or indeed the filter array) to revolve, bysimply arranging suitably-configured fins on the revolving item to catchthe rising air. Alternatively, of course, many other possible actuatormeans may be employed including, for example, materials which changetheir shape or dimensions according to their temperature, or accordingto electrical potential delivered to them.

The techniques explained in this document are, in addition to offeringexciting new display possibilities, also of high potential withapplication to simply dynamically changing the colour of light emittedby different light source(s).

In such applications as, for example, changing the colour of underwaterswimming pool lights, theatre, concert or floodlighting lightingsystems, domestic and architectural lighting application areas and soon, the use of a filter means capable of causing the light source toselectively emit more than one colour, and in addition an array oflenses, where a movement of said filter, or light source, and/or lens orlens array(s) causes the light to pass through a differentcolour/location, and thereby change the colour of the emitted light—insuch application areas (and many others), one great advantage of theabove system is that a very small movement can effect a universal colourchange.

In many cases where a ‘flat’, or ‘universal’ colour change is required(e.g., the theatre light is required to simply project a blue colour)the position of similarly-coloured ‘dots’ on the filter might well beidentical in the case of each ‘cell’. An alternative approach, however,where either there is a need to achieve more colours than there areavailable on the filter, would be to have different ‘cells’, or groupsof ‘cells’, using different colours in different locations in respect oftheir adjacent lens; using this approach, whether different cells (orgroups of them) are separately addressable and separately controllableor not, it will be possible to produce ‘combination colours’ which wouldnot otherwise be possible, or would be difficult to achieve.

Optionally, a scattering layer may be incorporated within the system soas to better ‘merge’ different colours simultaneously produced by thesame lamp, or lens array.

Optionally, (an) additional lens(es) may be used in front of thelens(es) through which the filtered light is transmitted to the exteriorworld, so as to, for example, better align their light paths, or morefocussed

Lenticular arrays can also be used to defract light: twosuitably-configured arrays, for example, arranged so that light passesfirst through one, and then the other, can be used to bend light so thatit can be directed at desired angles without having to move the lamp.The other axis of movement could be provided by revolving the lenticulararray to an appropriate angle.

Application of Physical Pressure to a Lenticular Screen can be used toChange the Perceived Colour—or Indeed the Perceived Image(s) on theScreen

FIG. 18 shows an example of how a lens array arranged in respect of amulticoloured filter can be used as an indicator means.

FIG. 18 shows, in cross section, two lenses of a lenticular screen whichpreferably incorporates many further such lenses.

As the screen, or section of the screen, is pressed downwards—say, by afinger—the screen changes is ‘latitudinal’ position vis-à-vis the imagecarrier means, thereby changing the image, or colour (if the ‘rainbowbars approach is used on the image carrier) perceived by the viewer.

In the above system, one (optional) advantageous approach would be toprovide means whereby the image carrier means is also pushed down as thelenticular screen is pushed down; in this way, the distance between thelenticular screen and the image carrier means would not change, but thepositioning of the screen vis-à-vis the indicia carrier wouldchange—i.e., the screen has moved to the right, but the indicia carrierhas only moved downwards with the screen. Since the ‘lateralpositioning’ of the two has thus changed, the image (or colour)perceived by the viewer would change if the indicia or colours were soarranged on the indicia carrier that the lens shown at left is nowshowing the viewer, e.g., portion Y instead of one of the adjacentportions shown on the diagram.

It will be appreciated that if the arrangement shown above wasduplicated across the screen, and if all indicia segments marked ‘Y’were the currently-perceived segment, and if Y was coloured, say,red—then the viewer would perceive the entire screen as red coloured.(This assumes that the lenses' design and that of the whole device weresuch, of course, to ensure that the viewer would perceive the same imagesegment under each lens at the same time—i.e., all the yellows at thesame time, provided that is what was desired as the objective).

Clearly, the design shown above could be such that there was a resistingforce—a spring, for example—located within the design so that differentimages, for example, could be shown to the observer according to howmuch pressure was placed on the screen.

The screen could be designed—by being made of rigid material, forexample—so that pressure applied anywhere on the screen would cause anequal perceived change in image(s) as a result; alternatively, thescreen could be made more flexible, for example, so that the imagechange would be more localized to the area where the pressure wasapplied. In the latter case, of course, the screen could be treated ordesigned so that pressure applied at a certain point would cause an areaof predetermined dimensions and/or shape to change: thus, pressing overa particular item—say, a picture of Bugs Bunny—would cause the entirearea occupied by Bugs to appear to change his appearance or posture, forexample, even if only his head had been touched. Such a result could,for example, be achieved by the area around, in this example, Bugs beingrigid, but there being a flexible area between the ‘Bugs area’ and otherareas so that pressure on the Bugs area did not cause a change in theperceived content of adjacent or other areas of the screen.Alternatively, of course, the ‘screen’ could in fact be a number ofseparate lenticular screens which, optionally, appeared to be a singlescreen, and which separate screens thus moved separately andindependently of any other lenticular screens.

Optionally, detection means could be incorporated within thelenticular/image assembly so that associated electronics would be ableto determine which area of the whole lenticular screen, or which of anumber of different lenticular screens, had been touched, or otherwiseactivated. One simple way of achieving this would be to lay downconductive lines—preferably transparent—on, for example, the undersideof the lenticular screen, and the top side of the image carrier means,so that when certain of those conductive lines were connected as aresult, for example, of physical pressure on the lenticular screen, anelectrical circuit was made, and was relayed to the controllingelectronics.

Using suchlike detection means, it would be possible to activate, forexample, the playing out of audio messages appropriate to thatparticular location on the screen. Using the Bugs Bunny example above,it could thus be arranged that when the ‘Bugs area’ was pressed down,and the change in position of screen to indicia substrate caused anumber of different ‘image frames’ of Bugs jumping up and down to beshown to the viewer, a sound file—stored, for example, on a sound IC ora digital disc—to be played out through one or more speakersincorporated with, or associated with, the display means. Thus, as Bugsappeared to jump up and down, he might be heard to shout out: “Yow—thathurt!”

We have seen the example above showing how pressure applied to thelenticular screen could change the perceived images from the point ofview of the observer of the screen. In fact, this is only one of verymany ways that a change in the orientation, or relative position(s), ofthe lenticular screen and/or the image carrier can cause one or morechanges to the perceived visual content of the screen, or sub-section ofthe screen. It can readily be appreciated that such a change inperceived image content could be achieved by any means that caused thesaid change in position or orientation of the screen and/or indiciacarrier. Any suitable actuator means may be used. Other examples ofactuator means that could cause such a change include the following:

-   (a) Motor means: any type of electric or other motor shifting    position or orientation;-   (b) Heat or temperature change could cause an expansion or    contraction of any material integral to, or mechanically associated    with, either screen or carrier means, thereby changing the perceived    images;-   (c) Change in atmospheric pressure could work in a manner quite    similar to that shown above for physical pressure—thus, for example,    a change in the perceived colour of a section of the bottle top of a    soda bottle could indicate whether it was still ‘fizzy’ or not;

Physical manipulation can be used to change an image in other ways.Citing the above example of a soda bottle, for example: by opening thebottle top, a cam surface for example running around the circularperimeter of the top could cause a lens array to move sideways inrespect of the image array underneath—and so cause the image to changeto display a number of different images on the bottle top as it isopened (and/or closed).

Materials which change their shape or dimensions in response to changesin temperature, or electrical potential delivered to said materials.

FIG. 19 illustrates one possible means by which two or more differentimages could be displayed on an enclosing device such as a bottle top.Of course, the same method could be used in any suitable situation wheresomething is opened, or mechanically operated in any suitable way.

Ratcheting or Locking Means to Visually Confirm Whether or not a CertainChange in Status has Ever Occurred.

For applications where it is desired that a visual confirmation beprovided for whether or not some change has or has not taken place, alens or lens array+multicoloured image or filter substrate a provides aconvenient means of achieving this objective.

If the device was adapted to be able to detect what (for example,mechanical) if any changes had occurred with respect, for example, towhether a taxi meter or gas meter, or perhaps a piece of electronicequipment, had been interfered since it was manufactured or fitted, aratcheting, or other locking means, versions of the systems describedabove could be used to reveal whether the lens/lens array had been movedwith respect to any filter array, so that once the orientation and/orposition of the screen or carrier means had changed as a result of saidstatus change, the position or orientation of the carrier means and/orthe screen would be irreversibly locked, and, for example, a differentcolour, or message, alerting viewers to the fact that they had beenmoved, would be displayed.

One of the many possible application of this technology idea would befor security purposes. For example, a lenticular or other lens devicecould be designed which would give a permanent indication of whether ornot any attempt had been made to open a certain item—for example, a foodpackaging item.

FIG. 20, which is out of scale and simplified for the purposes ofclarity, illustrates one means by which a lenticular display item suchas has been described could be designed. If the lenticular screen ismoved to the right, that movement of the screen will cause the lenses onthe screen to display images, or colours, which were not visible to theviewer prior to that movement.

Any locking means—one of many possible alternative versions of which isshown—to prevent the lenticular screen from being moved back again willthus ensure that inspection of the screen at a later time will clearlyreveal that the relative positions of screen and/or substrate bearingvisual indicia have been changed—e.g., that the perceived colour of thescreen has changed, say, from a green colour to a red colour, or that amessage has appeared on the screen saying “This has been interferedwith!”, which was not previously visible to the viewer—perhaps from aspecific angle.

This does, of course, presuppose that it is not possible to move thescreen so far to the right that the original appearance of the screenbefore it was moved can be achieved again! (i.e., that the screen wasmoved, for example, the full width of one or more lenses). Of course,the substrate bearing visual indicia could equally well have been movedinstead, or, in addition to the screen, if the design was thus intended,to achieve a similar function.

Means of Ensuring that a Lenticular Device is Viewed from a RestrictedRange of Angles.

With many of the lenticular display devices outlined in this document,there will be situations where it is desirable to ensure that onlyobservers in certain locations, or orientations, in respect of thedisplay screen are able to see the images displayed. This would, forexample, be particularly important in the case of security devices,where it might be essential that there was no possibility of someonelooking at the device from a certain angle could see an image that itwas not intended that they should see—for example, if either thelenticular screen, and/or the image substrate, of a lenticular displaydevice such as those described above, being used to indicate whether ornot a food packaging item, for example, had had its position moved, andas a result should be displaying a red colour across its screen, itwould be important that the consumer could not view it from any angle soas to perceive the screen colour as Green—indicating that it had notbeen interfered with, or opened (unless, of course, it was).

To achieve this purpose, it would be important in such situations toensure that the observer of the screen can only view it from such anglesas would provide them with the image(s) which were appropriate. Thisfunction of restricting the viewer's point of view, or angle ofobservation, can be achieved in many ways.

One means is simply to provide a shield around the screen, so as toprevent viewing from any but the desired angles.

In FIG. 21 a person whose eyes are located as shown will not be able tosee the screen. Clearly, the shields are non-transparent; their depthcan be determined so that it is adequate to ensure that no one could seethe display from an angle which would allow them to see an inappropriateimage.

An alternative approach to achieving the same objective would be toplace any filter means between the observer and the screen that wouldact, in effect, rather like Venetian blinds—i.e., would act like slatsthrough which the screen is viewed. This could be achieved, for example,with polarised light filter which only allowed light to pass out of theobserver's side of the screen in a fixed direction—or in a predeterminedrange of different possible directions, none of which would allow theobserver to see indicia derived from the indicia carrier means which itwas not designed to show them at that time.

Very crudely drawn, FIG. 22 shows a means by which the paths of lightthrough the image substrate and the lenticular screen can be limited.

Another means of restricting the observer's ability to see images orcolours on a movable indicia-bearing, or multi-coloured filter-bearingsubstrate suitably arranged in respect of the lens is to providelight-reflecting surfaces between said lens and said substrate, so as toreflect that otherwise would have flowed towards unwanted visualmaterial to be instead reflected towards the items it is desired thatthe observer should see. This approach is illustrated in FIG. 23.

Light-Reflecting Means of Attracting Attention by Moving Lens or ‘gate’Arrays in Respect of Multi-Coloured Filter Arrays or Visual IndiciaIncorporating More than One Colour, or light-Reflecting andNon-Reflecting Elements

In many situations such where it is important to attract the attentionof people, a means to do so which flashes, or frequently changes itsappearance, has been shown to be more effective in attracting attentionthan displayed messages, signs, etc. which do not change theirappearance.

To take a commonly-occurring example, where road repair work is takingplace, or other road-related hazard exists, and drivers of, for example,cars consequently need to be alerted to such potential danger, a commonmeans of alerting them is to use hazard-indicating lights surroundingthe site(s) in question: these lights may flash on and off to be moreeffective in attracting attention.

One weakness of such (often battery-driven) illuminated lamps, etc. isthat they rely on battery power, and consequently need to have theirbatteries recharged or replaced quite frequently. If, however, lightreflectors had been located around a hazardous location, they wouldrequire no battery power, but would be presumed by many people to beless effective at attracting drivers attention than a powered lamp wouldbe.

The invention proposed here is aimed at achieving a compromise betweenthe battery consumption of lamps which may be flashing when in use onthe one hand, and light reflectors on the other.

The proposed invention incorporates one or more lens, and one or morelight reflector, at least one of which moves in relation to the other,so that light falling onto said light reflector may be perceived asflashing on and off due to the aforesaid movement, or may alternativelybe perceived to be changing colour if, in an alternative designincorporating differently-coloured light filters or coloured indicia(preferably themselves being highly light-reflective, or incorporatingreflecting material behind them), the lens focussing light onto saiditems moves in respect of said differently-coloured filters or indicia.

An example of such a dynamically-changing reflective sign is shown inFIG. 24. Here we see an array of lenses, with light being directed ontoa surface incorporating, alternatively, light-reflecting andnon-reflecting elements. If said surface—as is indicated by thetwo-direction arrow—is moved regularly back and forth sideways inrespect of the lens array, it will be appreciated that, with suitablelight conditions (such, for example, as would occur if the sign wasfacing on-coming traffic at night)—then the device shown below wouldappear to alternately ‘flash’, because some of the light from, say, thecar's headlamps would be alternately reflected back towards thedriver—and then not reflected towards the driver.

Clearly, a similar result would be achieved if the lens array had beenmoved, and the reflective array-bearing surface had been stationary—or,optionally, they had both moved sideways.

It will further be appreciated that whilst in the simple drawing shown,the system simply either reflected light back, or did not reflect itback (or at least, to a less extent than before), the same fundamentalapproach could be employed to change the colour of the light reflected(by, for example, moving a multi-coloured substrate (preferablysideways) in respect of the lens array and in front of alight-reflective surface). Alternatively, of course, the substratebearing multiple coloured elements might comprise one or more images,different parts of which may be viewed when the lens-substrate specialrelationship is changed, so that the viewer of said display mean sees anumber of different images, one after another, displayed within the samespace.

The same basic approach can be used with many different shapes oflight-reflector, including reflective arrays which are designed toreflect the light back to the direction from which it came.

Lenses need not necessarily be used: any method of obstructing, orrefracting, or reflecting, light may alternatively be used, providedthat the movement of one or more substrate or item(s) bearing visualindicia or multiple colours, or incorporating different light-reflectingqualities, causes different portions of said surface of item to bevisible to a stationary observer through a relatively brief period oftime—say within at most 15 seconds. Thus, for example, an array ofprisms designed to reflect light back towards its source—often used inroad-related situations—could be used instead of the lens array,provided that movement of another surface or item as described abovecaused a change in the light reflected back towards the light source.

Any suitable actuator means may be employed to drive the movement ofwhichever of the above-described systems are designed to move. Ifbattery power is used, it will be appreciated that the consumption ofpower to drive, for example, a pendulum-type movement of said indicia orfilter-bearing substrate (or the lens array) should be far less withproper design than that required to generate flashing lights.

Static Lens-Bearing Displays Arranged to Appear to ‘Flash’, or ChangeColour, Due to Variable Reflective Properties over a Sign, Caused byApproaching Motorists' Change of Location in Respect of the Lens Arrayand Reflective Devices on the Sign.

In this invention, we are taking advantage of the fact that in manysituations relating to alerting motorists to dangers on the road, it isfairly predicable which direction said motorists will be approaching thedanger (or other subject of a sign) from, if the sign employing thisinvention is to be located along a single road, for example. We can alsobe relatively certain that in most cases, the motorists' speed will fallwithin a certain range.

It is well-known that lens arrays suitably arranged in respect of visualindicia lying behind them can be viewed from different angles, anddifferent images thereby perceived.

Taking advantage of the above generally-true suppositions about roadsign situations, a suitable arrangement of lenses and reflectivesurfaces and/or visual indicia suitably arranged in respect of eachother, such arrangements as have been described above for changingmessages when perceived from different angles can be used to change themessages visible to (e.g.) motorists driving along a road towards a signso that they see a series of different messages as they approach it.Optionally, such signs might incorporate reflective designs andmaterials especially suitable for reflecting car headlamps at night.FIG. 25 illustrates the approach.

The car is shown approaching the sign located at the top left of thepicture. The sign incorporates a lens array and coloured indiciarepresenting the ‘Stop!’ message shown as being perceived, in a flashingon and off manner, as the motorist approaches the sign. Optionally,suitable reflective materials of suitable shape may be located behindthe visual indicia if it is transparent.

The effect described above is achieved by suitably-designed lens arraysand visual indicia, by methods well-known to those skilled in the art.As an alternative version of the same principle, reflectors may be soarranged, with either lenses or prisms associated with them, so thatinstead of seeing an image, or a colour change, the viewer of the signswould simply see a reflection, and then a lack of reflection. Thus, thisapproach could alternatively be used for hazard warnings, etc. ratherthan, say, road-side signs.

The lens array used may in many cases be of a lenticular design; thelenses may be vertically or horizontally-oriented—the choice of whichorientation will generally be dictated by in which axis the approaching(e.g., motorist) will travel through the greater number of degrees ofangle in respect of the sign. Thus, on a road which is winding madly, itthe lens orientation might best be lateral, since the observer may wellbe observing the sign ‘Danger! Sharp Bends!’ from a wide range ofdifferent angles as he, for example, approaches the next curve. In othersituations, shown, for example, in FIG. 26, the sign could be located ata suitable height above the road, thereby taking advantage of thedifferent angles that the sign will appear at to the approaching driveras he nears the sign.

Arrangements Whereby Lens Array(s) and Reflective or MulticolouredFilter Arrays are Permitted to Move Freely in Respect of each other inat least One Plane for the Purpose of Presenting a Display Means whichChanges when one or both of the above Move in Respect of Each Other.

As a simple example of the invention, take, a child's pencil case orsatchel, where one or more sides of the case are (preferably) flat.

Let us suppose that the outer face of the side in question is somanufactured/designed so as to function as an array of lenses; andfurther, that underneath this outer surface is a compartment containingany suitable item or items incorporating different colours, or othervisual indicia, or variably-reflecting surface(s).

If we imagine for the purposes of this example that the item describedis made or rigid or flexible plastic, and that the dimensions of themulti-coloured substrate (as shown in FIG. 27) are less than thedimensions of the compartment containing said substrate. Preferably,there is provided in the assembly a means of facilitating the movementof the item(s) of multiple colour-bearing visual indicia—oil, or water,for example.

FIG. 27 shows such a layout: note that the substrate bearing visualindicia/multiple colours in, say, a patterned layout, is less than thedimensions of the compartment it is located within, and that it is thusfree to move—laterally, at least—as a result of any force—say, gravityor momentum—being applied to it.

Clearly, when the substrate bearing multiple colours or visual indiciadoes move, the images/colours observed through the lenses shown willchange. This will provide an entertaining, frequently-changing displaywhich, properly designed and presented, should be attractive andinteresting.

Preferably in a design such as that shown above, the depth of thecompartment would be the minimum necessary to allow the substrate tomove freely: this would be particularly important if such differentvisual indicia as text or clear graphic designs would be displayedaccording to the respective locations of the lens array and theimage-bearing substrate, as excessive depth of the compartment wouldincrease the risk of items becoming out of focus.

Clearly, if desired, the lens or lens array could instead—or inaddition—be the mobile item in the above design, provided that visualindicia-bearing means were provided behind (from the observer's point ofview) the lens or lens array.

Clearly, the image or colour-bearing item(s) need not be located on asubstrate: they could, alternatively for example, be a large number ofsmall coloured spheres which circulated around the compartment.

Equally, the compartment, or the context, in which this approach istaken to provide a frequently-changing display caused by changes inforces applied to the lens array and/or the image or colour-bearingitem, need not be restricted to rigid or flat items. The same approach,for example, could be used in material used for clothing.

Optionally, means may be incorporated to allow a person to displace thelens array or lens in respect of the coloured or variably-reflectivesubstrate or item, so as to change the display.

Other Colour-Changing Applications

Apart from the use of such display means as are discussed elsewhere inthis document, the same fundamental methods can be applied to otherapplication areas—a few examples of which are discussed briefly below.

Multiple Message/Image Roadside/Traffic Signs with Actuator Means

The above arrangement, and in addition many of the otherimage-changing/colour changing approaches discussed in this document—maybe advantageously used for any kind of sign where multipleimages/messages, or moving images/messages, are desired.

Taking traffic and roadside signs as an example, with the use of thedisplay-changing methods discussed herein, they can change themessage/image displayed according to any variable—e.g., time of day,weather conditions, amount of traffic, etc. Optionally, they mayincorporate their own sensors to enable them to change the displayedimage according to predetermined conditions. Optionally, they may beconnected to a message-carrying means—e.g., a phone line or a radioreceiver—so that their status may be remotely controlled—for example bypager messages, for example.

In FIG. 28 the left-hand message may for example be displayed at one endof a road at most hours of the day, but may change into the right-handdisplay message during rush hours—so that the road becomes a one-waystreet during busy times.

Thus, in the illustration above, the signs could for example incorporatea lens array and an image-bearing substrate, with a suitable actuatormeans, control means (e.g., a microprocessor) and power supply (abattery, or connection to mains power supply) to fulfil its function ofdisplaying different messages to different parties approaching it, oraccording to other changeable factors such as traffic flow rate, time ofday, etc.

Optionally, reflectors may be located behind each ‘cell’ so as tofunction in a similar manner to ‘cats eyes’ used on roads to assistdrivers at night, so that the displayed messages may work at day ornight.

Time/Time-Code-Determined Broadcast Item Logging/Ordering System

There is a lot of work currently been devoted to allowingviewers/listeners of broadcasts or transmissions on TV, radio, fromsatellite or down cable, on the Net or the like a means of convenientlyidentifying items of interest to them which are broadcast, and torequest further data relating to that item or items, and/or to ordergoods or services related to that item or items.

Many of the devices hitherto invented rely on some additionalelectronics which is added to that provided in standard televisions,taking the form of some ‘box of electronics’ which the user attaches tothe television by some means. Clearly in the future it is envisaged thatsuch facilities as are provided by such ‘set top boxes’ may beincorporated within the TVs themselves.

The disadvantage of such systems is that owners of existing(conventional) models of televisions must be induced to pay for such‘set top boxes’—or alternatively some service provider has to pay forthem. The costs involved can be substantial, when the number of boxesthat need to be provided is taken into account.

It would clearly be very desirable to have a means by whichviewers/listeners of such transmissions may be able to achieve theabove-outlined functions without significant expenditure on newequipment.

In addition to the above, there has been a lot of attention devoted todelivering personalised program-making or selecting means to viewers oftelevisions (and indeed listeners to radio). There have, however, beendifficulties is unifying such personalisation means so that most or allbroadcasters cooperate in including their own broadcast informationwithin such systems.

My invention is this: a device which simply logs a time-related numberor code when the user/viewer/listener of a transmission sees an item ofinterest, and indicates that interest by, for example, pressing a buttonassociated with said device. The moment that said interest is indicated,the device will store both the time-code associated with that instant intime, as well as the channel (or site, for example, in the case of theNet) that the user was viewing or listening to at that moment.

By this means, sufficient information is acquired by the device toprecisely identify what images/sound were being transmitted on thatchannel at the precise time that the viewer indicated their interest byactivating a switch of some kind.

The device will preferably incorporate sufficient memory to store theabove information for later recall—or will, or can be, linked to one ormore other devices with which it is able to communicate, by any suitablemeans, where such remote computers or devices can themselves store theabove ‘time-code+channel’ information.

Optionally, the device may incorporate a means of playing out,communicating to other devices, or displaying, a code which incorporatesboth the time-code and channel information.

Optionally, the device may incorporate means of generating signals ofany kind which may be used by the user to communicate the aboveinformation to other devices. Such communication may, for example, takeplace down a telephone line. In such an instance, the user might liftthe phone (or otherwise obtain a line) and might press a particularbutton, for example, whereupon the device would generate a series oftones which would cause a connection via the telephone line to be madeto a remote computer or server or other suitably-equipped device whichis also connected to the phone network, and to which said user's deviceis able to communicate choices made by said user with regard topurchasing items or services advertised on the radio or TV or internet,etc., or relating to requests for further information, and so on. Ofcourse, instead of communicating with a remote computer or the like, theperson using the user device to make the phone call may instead talkwith a human operator, having preferably been connected to him or her bythe tones generated by the user device.

When the two devices are in communication with each other, thetransmission ‘time+channel logging device’ could transmit signalsindicating one or more ‘channel+time-code’ combinations. The remotedevice could simply record that information which would at that time orlater be matched to whatever item(s) was/were transmitted on that orthose channels at that or those times indicated by the time-code(s) inquestion. Said remote device, which may be a computer or server, couldthen communicate instructions to, for example, parties supplyingrequested goods or services to order them to provide the applicablegoods or services related to the aforesaid broadcasted material whichinterested the user of the user device.

Optionally, if the user of the device wished to purchase a good orservice related to the item of their expressed interest, they couldthen, for example, provide the remote device—or, clearly a human inplace of such remote computer or other device—with a credit card numberto facilitate their purchase of the good or service desired.Alternatively, of course, said credit card or other payment informationmay be pre-stored by the remote party, and then perhaps all that wouldbe required would be some form of ID presentation by the user to confirmtheir identity—e.g., a PIN code.

Optionally, the information transmitted by the remote control devicecould provide further information identifying the device or the owner ofthe device for authentication or other purposes. Optionally, the deviceor person at the other end of the phone line may, having matched thetime-code and the channel information to the particular transmittedimages or sound in question, then or later confirm to the device userthe items in which it appears they expressed interest, for furtherconfirmation by said user that that information is correct.

Optionally, the capabilities of the device, or equipment to complementsuch a device as has been described, and/or alternative derivativeversions relating to those ideas described above, could be incorporatedinto televisions, radios and the like.

Optionally, the above-listed capabilities or any reasonable combinationof them could be incorporated within an infra-red or R/F remotecontroller of, for example, a television. The remote control devicewould communicate to the TV's controlling electronics via infra-red,acoustic, electromagnetic or R/F which channel the viewer wishes towatch at any time. Said remote controller would further incorporate atiming device which would record or ‘log’ a time-code every time theviewer activates one or more appropriate switch means preferablyincorporated into said remote controller which indicate the user'sinterest in an item they see displayed, or otherwise referred to, on thescreen.

Optionally, a device separate from the remote controller may be used;such a device would log the time-code as above, but would require thatthe user indicated to the device which channel they were watching thatcontained the item of interest.

Optionally, the controlling device which logs a time-related code eachtime the viewer expresses interest in any time broadcast, and which alsostores information relating to what channel was being watched at thattime, may in addition incorporate means of receiving R/F, optical,acoustic, electromagnetic or other types of signals from an externalsource to ensure that the timing device on-board the remote controllerremains accurate. The TV controller would thus correct its internaltime-measurement system if there was a discrepancy between its ownperception of time and that transmitted to it by the internal source, sothat it agreed with the external source. Such a receiving device might,for example, take the form of a radio receiver to receive signals from‘atomic clocks’.

Optionally, said TV controller would incorporate facilities forreceiving signals radio or other signals associated directly with thetransmission signals made to the television or other device such as aradio, or computer linked to the internet, etc., which is currentlybeing watched or listened to. Such signals may incorporate sufficientdata about the transmissions in which the user may wish to expressinterest that a timing device may not need to be incorporated withinsaid controller or ‘zapper’ device. Such ‘side-band’ or otherchannel-associated data transmissions received by said controller may,for example, include data which uniquely identifies the material watchedor listened to by the user at any or most times that they would be able,or likely, to activate switch means preferably incorporated within thecontroller which would identify their wish to order items, obtainrelated services, or obtain other information, etc.

Optionally, the device itself may not incorporate a timing device, butmay instead rely totally on receiving such externally-generatedtransmissions to determine a time-log when a viewer expresses interest.

Alternatively, such a device may contain instead an R/F or othertransmitter which may communicate to a separate, remote, receiver theinstant that the user touches the button associated with an expressionof interest in the viewed or heard item together with an identificationof which channel was being watched or listened to at that time. Theremote device would in such a case then log the time-code associatedwith that transmission. Alternatively, information uniquely identifyingthe transmission in which the user had interest could be stored by thecontroller, and passed to such a remote receiving device at a latertime.

Optionally, any of the above-described devices (or any combinationthereof) may incorporate an R/F or other receiver which receivestransmissions from a remote transmitter or transmitters containing datarelating to items which are, or have been transmitted on one or morechannels. The above-described device could, for example, by monitoringsuch information, match-up the channel and time-code information todetermine a code for said item of user's interest, which could then betransmitted directly by any means to suitable goods or service provider,thereby not requiring that provider to do the matching processthemselves.

Such a methodology as is described above could alternatively beemployed, for example, to instruct a video or audio recorder or the liketo make a recording associated with an item transmitted at the time ofexpressed interest by the user. Thus, for example, if the viewer waswatching an item on TV or other broadcast channel (e.g., radio, theinternet, etc.) informing viewers/listeners that a documentary on EastAfrican wildlife would be made on Friday of the following week at, say,9.30 p.m.: if the viewer pressed the button indicating interest/desireto record the program/desire to be reminded of the program at that timeor within a permitted period of time or by appropriate means that woulduniquely identify his/her interest as being in that particular item, thetime-log (or other unique identifying data, as described above,associated with the operation of the switch means used by the user wouldbe stored in the device, or an associated device to which it couldcommunicate said data, together with the channel information, and thatdata could be matched up with data received via the R/F or otherreceiver, allowing the device's control electronics to determine a codeindicating what channel and at what time—and, optionally, the start andfinish of such transmission.

The device could then (a) transmit an instruction to said video or audiorecording device to make a recording on that channel at that time,and/or (b) could alternatively simply remind the user by any suitablemeans at or before the transmission time that they had expressed a wishto see that program—for example, the device could emit a bleeping sound,or could transmit an appropriate message by any suitable means to theuser reminding them of their previously-favoured choice; or (c) thedevice could simply at the anticipated time and channel of that program,switch the TV on (if currently off) and to that channel in question, byIR or other appropriate means. Clearly, if infra-red means wasincorporated in the controller for suchlike purpose, then the controllerwould have to be in a line-of-sight position in relation to the (e.g.)TV in order to turn it on!

Optionally, the controller device might then switch off the TV if theuser does not indicate to the device (by, for example, pressing adesignated button) that they wish to watch that program (or are indeedpresent at all). The means of reminding the user of the program theyexpressed a desire to watch could be provided simply by generating asound from sound-generator on-board the device or flashing a light, ordisplaying the relevant information on a screen on-board the device.

Optionally, such a received data stream from a remote source may containinformation beyond that outlined above: for example, if a viewer waswatching MTV, they may wish, during a certain program, to indicate tothe device the desire to buy copies of a number of different pieces ofrecorded music. The device bearing an (e.g., R/F) receiver may obtainfrom the received data stream not only an identification of whichproduct (i.e., songs) match up to the selected time-codes, but may inaddition receive information relating, for example, to the playinglength of those particular songs, so that the device may alert the userwhen he/she has ‘ordered’ songs which in total have reached a playinglength close to the limits of that recordable on a CD, for example,which the product provider will record with the user's designated songs.

Clearly, such facilities and capabilities as described in any of theversions listed above could be equally well applied to a radio or otherdevice receiving a stream of transmitted information where the item inwhich the user was interested can be identified by determining what wastransmitted to the user on that particular channel at that particulartime.

Scrolling Retractable Keyboard for Telephones, Computers, ElectronicOrganisers and the Like.

One of the problems with electronic organisers, small computers of verysmall physical size, mobile telephones and suchlike small-sizedelectronic processing or communicating devices, is that due to theirsmall physical size, it is often not easy to operate the small keyboardsthat are usually integral to such units.

Whilst a mobile phone's numeric keyboard, for example, may be quiteadequate in size for dialling numbers, or even tapping in very shortsentences for text messages, it is certainly less convenient and easy touse than, say, a PC's standard-sized keyboard.

My invention (see diagram below) is a rolled-up keyboard which isintegral to, or which optionally is attachable to, such small-sizedelectronic devices, and which may be unrolled from its unused positionwrapped around a roller system when it is to be used as a keypad orkeyboard. By this means, a keyboard of larger size than the physicaldimensions of any one face of such aforesaid small electronic devicescan be conveniently stored in a small space when not required, andquickly unrolled for use when a keypad is required.

FIG. 29 illustrates this idea: in a design approach in essence similarto that of a retractable tape measure, a keypad of suitable design so asto render it extremely thin and flexible, is stored on a roller-typedevice which is optionally spring-loaded so as to retract (or,optionally, extend) automatically when an appropriately-located releasemeans to achieve this is activated by the user.

The keyboard may be made of any suitable flexible material which may berolled up on a roller within the storage facility integral to, orattached to, the electronic device.

The keyboard may, optionally, be composed of a number of flexiblesubstrates with appropriately-positioned electrically conductive, andinsulating, elements integral to the design (in one possible designapproach similar, for example, to a conventional membrane keypad),wherein pressure (or the presence of a finger detected by any suitablesensor means) is applied at pre-designated and, preferably, labelledlocations on the key pad and thereby causes two or more electricallyconductive elements to touch, or any other switch means to be connected,and thereby to make an electrical circuit. The conductive elements willmove to separate from each other again when the pressure is released.Such a design approach to a keypad is well-established.

Alternatively, the keyboard could be designed and made on the basis ofany suitable and practicable switch means, whereby the pressure of, orpresence of, a finger (for example) activates a switch means, which thencauses an electrical circuit to be made or broken. As an example of aswitch means where an electrical contact is not physically made, acapacitive keypad could optionally be used.

The keyboard may be electrically linked to the aforesaid smallelectronic device by any suitable means. Alternatively, the keypad maycommunicate with the small electronic device via any suitable remotecommunication device—e.g., optical, R/F, electromagnetic, capacitive,inductive, etc.

Optionally, the extendable, ‘roll-out’ keypad may duplicate some, orall, of the functions of a separate keypad which may be integral to theaforesaid electronic device.

Cellular Phone Ringer Sound Volume Control System

(a) Ambient Noise Level-Determination of Cellular Phone Ringer or‘Incoming Call Alert’ Volume Level

Owners and users of mobile phones often find that their mobile phoneseither ring too loudly, or too softly, for the environments in which theuser is at the moment of the incoming call.

In an expensive restaurant, a library or suchlike quiet place, theringing sound of a mobile can seem extremely loud, and can causeannoyance to others, or embarrassment to the owner. This can beparticularly inconvenient where the ringing volume had previously beenturned up to accommodate a noisy environment.

Conversely, a mobile phone which has been turned down to meet the needsof a quiet environment may not be heard when it rings in a noisierplace.

To alleviate this problem, my invention here is any suitable means bywhich a cellular phone is adapted to ‘sample’ the ambient noise levelsthrough any microphone Incorporated within, or associated with, saidphone, so as to determine the volume of ambient noise In the currentenvironment, and to adjust the volume of the ringer soundaccordingly—I.e., to reduce for a quiet environment, and visa-versa.Such sampling would preferably be undertaken prior to generating the‘ringing sound’, but can, of course, be adjusted during the period overwhich the ‘ringing sound’ is generated.

There are many different means of achieving this functionality, all ofwhich will be well-known to those skilled In the art.

Optionally, the nature of the ‘incoming call alert’ could be modified—inpitch, rhythm, frequency or otherwise—to prove most likely to attractthe user's attention in the context of the level and/or particularnature of the environmental, or ambient sound that is perceived througha microphone incorporated within the mobile phone.

The above Invention Is also applicable for any other electronic deviceswhich make ‘alert’ sounds to draw the attention of the user.

(b) Analysis of the Nature of the Mobile Phone's Environment:

As a related invention, it should be noted that whilst the above ambientnoise-determined volume control system for incoming call announcement onmobile phones would prove useful and beneficial in many circumstances,there are a number of circumstances where solely relying on ameasurement of the amplitude of ambient noise would actually cause thephone to ring at a quite inappropriate level—too softly, or too loudly

For example, if placed inside a handbag, attache case or the pocket of acoat or jacket, where there might be little or no perceptible sound tobe detected, the phone might well, using the above soundamplitude-determined method, in fact play out its incoming callannouncement message quietly—where actually a very large amplitude ofsound would be required to enable the owner or user of the phone to hearthe announcement sound from within the case.

Conversely, a noise-making item very close to the mobile phone'smicrophone in an otherwise very quiet environment might cause thecontrolling electronics to making the incoming call announcement at avery high amplitude.

To help deal with such situations, and to provide a more sophisticatedmeans which may compliment and enhance approach (a) above, the mobilephone may be adapted to emit a sound from a noise-generating element—forexample, the phone's speaker—and to analyse that same sound with amicrophone Incorporated within the mobile phone. By well-known andconventional means, such considerations as the presence or absence of anecho, the sound level at which the microphone detects the soundgenerated by the noise-making device (e.g., the phone's speaker), andother related means of analysing the incoming signal for changes,muffling and distortions, the on-board microprocessor will In many casesbe able to make deductions about its environment.

For example, if the phone is in someone's pocket, the level or contentof the signal generated by the speaker and reaching (or not) themicrophone would indicate to the on-board microprocessor that somethingwas impeding the transmission of any signals made by the speaker. Suchcircumstances would make the generation of a louder ringing soundappropriate, to increase the chances of the phone user hearing theincoming call announcement.

Similarly, the rapid bounce-back of a signal generated by anoise-generator on-board the phone and detected by an on-boardmicrophone could indicate to the controlling electronics that the phoneis in a tightly-confined space—although not one impeding thetransmission of sound from noise-generator to microphone. Suchcircumstances would again tend to recommend playing out a much louderincoming call announcement sound.

The pitch or other controllable feature of the ‘Incoming call alert’sound could optionally be modified to reflect the microprocessor'sperception of the environment: If the feedback from the microphoneIndicated that, for example, the cellular phone was probably In aconfined, sound-deadening environment such as a pocket, or handbag, Inaddition to Increasing the amplitude of the alert sound, a higher pitchmight be used to better attract the attention of the phone owner oruser.

To prevent the noise-generating element from adversely affecting a userof the phone due to his/her close proximity to the phone at the time ofthe noise-generation, the ‘environment-testing’ noise generated wouldoptionally be ultrasonic. Optionally, proximity or other sensors couldbe incorporated into the phone to detect the nearby presence of aperson—capacitive or infra-red sensors might prove particularlysuitable.

Another important sensor system other than acoustic which would add tothe information available to the phone's controlling electronics is anoptical sensor.

An optical sensor can detect the ambient light conditions—and thus (asoutlined below) can calibrate the luminosity of the display. it canalso, when added to other information such as those described above,greatly add to the phone's controlling electronics' certainty about itsenvironment. For example, the absence of much or any light, combinedwith a ‘muffling’ of the detected signal generated by the phone, makesthe chances of the phone being in a pocket of similar container—and thusthe need for a high amplitude—or high frequency—of call announcement avery high probability. If the microprocessor took Into account thecurrent time of day, the degree of certainty of the meaning of low lightconditions could be further enhanced.

It should be noted that if the device continues to monitor the ambientnoise level as it ‘rings’, if the user, having heard the ringing fromwithin his attache case, then opens or moves it, the phone canimmediately lower the volume to reflect the new environmentalconditions. Such sensors as piezo electric or other movement sensorswould be suitable for detecting such movement of the phone, andaccordingly lowering the volume if appropriate.

Optical alert signals to attract the attention of the phone user can incertain circumstances can be far more effective than an acoustic signal.Where the detecting equipment Incorporated Into the phone determinesthat the noise level is very high, but that the phone is not confined,and that the light level is low, the controlling electronics mightactivate a high-brightness flashing LED or other light-emitting device,for example, as the most efficient way of drawing the phone user'sattention. In such environments as a noisy disco or music club, thismight well be the only way of attracting the user's attention.

Sensor or Switch Means to Reduce the Likelihood of Accidental Activationof the ‘Call’ Function on a Cellular Phone

Many users of cellular phones—particularly those models of phone whichdo not have a flap protecting the keyboard—have discovered at some timeor other that their mobile phone has actually connected Itself to thecellular network due to the appropriate ‘call’ key being accidentallydepressed. In fact many people have incurred very substantial phonebills as a result of such accidents, which perhaps most commonly occurwhen the phone Is placed In such locations as a pocket close to thebody, or within a handbag, etc.

There are many switch and sensor means well known to those skilled Inthe art which will not be activated—or are extremely unlikely to beactivated—by pressure being applied to their switch means. Such switchmeans Include those requiring some element of heat (such as wouldnormally be given off by a human finger), or a certain level ofelectrical conductivity or Impedance, or a certain level of dielectricconstant—and so on.

My Invention here Is any switch means on one or more keys of a cellularphone's keypad which will serve to connect a cellular phone to anetwork, or which serves to generate a call or otherwise Incur expenseto the user by using any facilities provided by any network to whichsaid phone Is or can be connected, where such switch or sensor meansrequires the detection of attributes on or adjacent to the surface ofsaid key or keys that would be unlikely to be possessed by Inanimateobjects pressing said key or keys, and that would however be very likelyto be possess by a human finger—for example, a certain temperaturerange, electric resistance levels, dielectric constant, and so on.

Whilst the focus of this embodiment is on the ‘call’ function button ofa phone, it is applicable to any other keys on a mobile telephone.

The invention has numerous applications in a multitude of applications.While the invention has been described with reference to preferredembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention.

In addition, many modifications may be made to adapt a particularsituation to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

1. A display device comprising: a first light-transmissive sheet havingan outer surface and an inner surface; a second light-transmissive sheethaving an outer surface and an inner surface; wherein one or both ofsaid inner surfaces of said light-transmissive sheets are hydrophobic;one or more measures of a light-transmissive liquid; a sealed spacebetween the inner surface of the first sheet and the inner surface ofthe second sheet, the liquid being enclosed within said sealed space; aplurality of multi-colored light filters comprising a plurality ofdifferently-colored elements being associated with each measure ofliquid; a plurality of electrical elements, located adjacent to, butelectrically insulated from, each liquid measure associated therewith; apower supply; and a microprocessor or other suitable means coupled tothe power supply and the electrical elements, capable of selectivelycontrolling the electrical potential delivered to each of saidelectrical elements so as to create an electric field affecting theassociated measure of liquid, thereby inducing a change in the locationor shape of said affected liquid measures, and thereby refracting andmodulating the direction of light passing through said liquid measuresto be directed onto or through selected colored areas of saidmulti-colored light filters.